https://www.dndbeyond.com/classes/cleric#ForgeDomain

If you have to "lay out" metal equal to the value of the item, what's the advantage of using this Channel Divinity?

I could just as easily say "I go find a store and buy the tools" as I could say "I spend an hour completing this ritual".

I mean, I get the whole "you can do it wherever you want, even when you can't access a shop". But that's a pretty niche circumstance, IMO. Certainly not enough to outweigh an entire class feature.

Thoughts?

You lay out the materials needed for the metal parts of the item.  Which is going to be cheaper than the metal parts and the non metal parts and the labor.

Edit:. I had misremembered the text, so above should just read "materials needed for the item.  Which is going to be cheaper than materials and labor."

Another niche use the ability implies is being able to copy (non-magical) important items.  I.e., steal the signet ring, copy it, and return it with no one being the wiser.

Quote from Pixel_Kitsune >>

You lay out the materials needed for the metal parts of the item.  Which is going to be cheaper than the metal parts and the non metal parts and the labor.

 The text says "As part of this ritual, you must lay out metal, which can include coins, with a value equal to the creation."

So you're not saving any money.

Depending on the DM fabrication materials is still cheaper than final cost including labor and merchant profit margin.  But I will edit my original post to fix the error.

Also depending on game.  Metal may be easier to get than other materials.

is it value of the final creation or only the value of the materials?

The value of the creation.

Meaning if you wanted to use the ability to craft Tinker's Tools, you'd need 50gp worth of metal/coins.

So besides really niche uses like "don't have access to a shop" or "need to create an exact replica of some item already possessed", this ability is a dud.

The party at my table basically uses this to convert 100gp worth of various equipment they pick up in their adventures to gold every day without having to go to town and sell it. One time the party came upon a teleportation circle and the cleric used this ability to make a medallion in the exact design of the circle so the party could reference it later. I thought that was fairly novel.

you could try to make a copy of an valuable artifact of religious significance (one that is valuable mostly for religious or artistic reasons) just to **** with the staff of a museum, or you might find an strange weapon whose design happens to be brilliant but whose method of construction has been lost to the ages, nobody knows how to make damaskus steel for instance, but with an divine blessing you can at least continue to forge weapons out of the material, or you might find an elven crafted double bladed scimitar and be clueless as to how they added the second blade without reducing efficiency or adding weight, and so with artisans blessing you are able to craft new double bladed scimitars. You might visit an beach and find an shipwreck of eastern design, and in the sands you find an katana, this incredibly light and sharp weapon that is supremely hard to create, and with a bit of gold and one hour, you can have another, so you can dual wield them. Your character might like the design of an scimitar and decide to copy it for yourself. 

You are the kenku of metalworking, and you are able to make anything, including rare metals you might be unable to get otherwise, rare alloys you you have no idea how to make and forgotten crafts.

in other words, if your campaign includes a lot of forgotten empires with cool technology or simply skilled craftsmen, this ability is an really potent storytelling device, especially if you play as an archaeologist type character. Or to put it in another simple set of words, this ability is great for making things shops probably do not sell like adamantine, silver, platinum etc. Also channel divinity is regained on a short rest, so you can spam a lot of short rests and a lot of uses of this ability in a single day, something that always should be noted

also if a wizards spellbook has a cover with metal elements and he has so far only added spells to it for free by his spellcasting feature as he levels up, you can copy the book and every spell within for the same price as buying an entirely new spellbook, but with all his or her spells already within it, since making the book only cost the wizard 50 gp, even if the value of adding spells to it is much more.

That one is likely going to run into DM fiat there, Artifice.  I know that as a DM, I would not allow someone to fabricate an entire, fully-loaded spellbook for fifty gold, no matter how much metal was in the cover.  You could get a second, blank (very nice) spellbook, but not one with spells in it.

Anyways.

Artisan's Blessing: 
-Turn up to 100gp of random flotsam into hard to locate objects, such as a full-up carriage in the case of one game we played (the player argued, successfully, that metal was involved in the fittings and assembly of a carriage, i.e. nails, springs, and other such objects)
-Turn up to 100gp of random flotsam into objects that might raise questions if purchased directly, such as thieves' tools, caltrops, or other useful-but-shady materials when in a town where such things cannot be readily sourced without arousing suspicion.
-Turn up to 100gp worth of barely-salable dungeon loot into 100gp ingots for easy transport and resale.  The Bank of the Allhammer always provides the best conversion rates.
-Turn scale mail damaged by a rust eater, and a spare dagger for raw material, into scale mail not damaged by a rust eater mid-dungeon.  Technically, rust eater damage (somehow) does not reduce the value of the armor according to RAW, and frankly I thought that was a clever enough use of the ability to let the cleric have it.  What's more 'Forge Domain'-y than fixing armor, after all?
-Turn up to 100gp of random flotsam into a series of busts of someone you're trying to find, gaining the advantages of exact likenesses (depending on how precise the cleric can be) when searching for that person.
-Turn up to 100gp of random flotsam into a series of busts of yourself you decorate with.  Because why not.
-Turn up to 100gp of random flotsam into components of something more expensive.  The Forge cleric in my game regularly uses Artisan's Blessing to help him maintain and repair his firearms.

The ability is very useful, but only in the hands of a creative player that's willing to accept it as a purely noncombat support/preparation ability.  Which is very fitting of the Forge Domain, at least in my eyes.

Also gonna throw this out here (though this is very setting/DM dependent), if you're running a campaign with sci fi elements and you run into a piece of advanced tech like a laser pistol/antimatter rifle from the DM's Guide or something similar, I'd say you could try to recreate it at least in part.

Admittedly, this is *very* much stretching the possibilities of what's allowable, but if you have a fairly permissive DM (like yours truly) then I'd say it has very strong potential.

It's a great ability, IMO, b/c you can use it to help solve a whole range of problems.  It's a multi-use tool for many unusual travails of adventurers.

   * Need nails on a deserted island to mount something on a jerry-rigged sailing vessel?  Create them.

   * Is a giant having a toothache?  Create tongs to extract the tooth.  Then create a metal tooth to put in its place.

  * Need to bribe someone who already seems to have everything that is purchasable?  Custom craft a small statue of their favorite thing/person that glistens in the sun.

  * If you meet someone who is constantly forgetting things, you can now make them a metal reminder plaque in just an hour.

If you play in settings with a lot of social encounters, political intrigue or deep dungeon delving where there aren't humanoids to buy and sell with, the value of Artisan's Blessing really shines.

much more reasonable if the gun itself in an blessing from the gods

If your DND world is like the USA, and you can always find whatever you need at the local store just a short drive away, this ability isn't as useful.  But if your DND world doesn't have fully stocked stores in every town where everything in the PHB is available for sale, and all of the materials you want are available for sale, this ability is a lot more useful.

It just depends on how your DM builds an economy - if he builds a modern colonial superpower economy, or if he builds an economy where scarcity exists.

or you use it to replicate objects you have one of, but need more. Most shops will not have bombs available for the public to use, and some technologies might be lost to time due to whatever reason, see damaskus steel for an real world example

The use of the ability is entirely dependent on your creativity and available resources, as well as your DM. For example, I once used it to give my ranger party member a new set of scale mail after salvaging every bladed weapon and arrow from a troupe of dead bandits. 

There is also the chance that your DM has npcs that try to haggle, in which case this ability to very useful as you could, in theory, convert items to their exact PHB price with this channel divinity.

It's not the most active ability but it's very good for creative players. If your character has the keen mind trait or your DM is pretty permissive on recent events you could reasonably recreate any important (but not drastically expensive) item you've seen in the last few hours/days. You could create a bag of ball bearings or caltrops from a few looted swords, cast heat metal on the entire bag, and throw them out like some sort of demented sadist. Or you could just see it as a "I don't have to go to the store right away" ability.

As written, I'm not sure the rules support casting Heat Metal on an entire bag of ball bearings.  As a DM however, I like the idea enough to permit it, though I'd rule that 1) you'd need to find a way to deliver them creatively if you don't want to take damage from it, 2) I'd probably have the enemy roll some sort of check to determine if they touch the bearings or not if they don't fall prone, and 3) I'd prooobably end up using that idea myself for a future encounter as well...  *rubs hands*

better yet: use caltroops to prevent escape and to make shure it penetrates the skin

As a DM I would rule that before being thrown the bags effectively count as 1 cluster-like item until being thrown, but after being thrown you would only be able to focus on one bearing at a time. My reasoning would be that, as armor has many interlocking parts and pieces that form the whole of the item, there are individual pieces of metal that form one bag of ball bearings. That being said,  the area they take up is only 10x10 ft, and even if your DM allows them to be considered as one whole item, I can't imagine it being a tactic you'd use constantly. In the instance I had tried it in, we were traveling in a narrow, tunnel-like dungeon with several choke points, so it made sense. In an open field, though? meh.  

Also I've totally used it against players, lmao. Chain-link sack, heat metal on sack full of ball bearings, throw high up and have it cover several portions of the battlefield. I made it so that if they moved at half speed through the area that it would count as them avoiding them entirely, for simplicity's sake, and if they wanted to rush towards the enemy they needed to make the save or find a way around.