Is the Grim Hollow Player Pack a one-off, or are [or could] player packs be a replacement for à la carte purchases?  

I'm not sure what's in the pack and what's in the main books to know the dynamics. It could work as an inferior version, I guess. The big draw of of piecemeal purchases was that they also discounted the main book though, so I don't know that this would be an acceptable substitute if they are the player options from a book. At $15, it's not cheap either.

It might be a new way for just getting the character creator options. Not as good as al a carte but better than nothing.

So until DDB gives an update, this is one of those "no one knows" things.  

It sounds like an experiment to 1.) bundle third party player options, which has never been done before.  2.) do it as a way to encourage player purchases and to some extend protect players from spoilers, maybe.  

I doubt we'll be hearing anything to the tune of "oh yeah, player packs are what we're doing from here on out" until they take some time to see how the product worked and whether it was worth DDB's bottom line time to do with other products.

So basically to answer the OP question, "Maybe?"

I would not read all that much into this.  D&D Beyond had a significant amount of DM-facing Grim Hollow content, but did not have any real player facing options.  This, if a DM wanted to run Grim Hollow using Beyond, they would not have the integrated tools to give players setting-specific options. 

This product patches that particular hole by introducing something for players to use in a Grim Hollow campaign.  At this time, with the limited data we have, the most likely conclusion appears to be that Beyond created this product to bring Grim Hollow up to speed with the other third-party offerings (both CR and Humblewood offered both DM and player facing content).  

I think it should be noted that Ghostfire does put out a player's guide for Grim Hollow with 24 subclasses and other player options including races and lineages and backgrounds.  The physical book with all that is 49.99, not sure how Grim Hollow is represented and at what price point it is in the VTT, digital tool space.   I'll let folks decide whether 14.99 for a quarter of the content, at least insofar as subclasses, is worth it.  When Grim Hollow debuted on the DDB marketplace, "what about the player guide?" was asked.

I do believe Grim Hollow bolted on a lot of sub systems and mechanics to its sort of grim gothic brand of D&D, and that could explain the truncated player offering.  Some of what's in Grim Hollow may not be currently tenable on DDB.  So I do see this as another experiment on handling popular third party in the marketplace (Grim Hollow had been asked for on DDB a lot more than Humblewood, though frankly Humblewood's original book's player options are easier to homebrew than some WotC player options.  Grim Hollow is a bit crunchier).

I bet that all third party content is fully controlled by the third party in this case Ghostfire

How its sold what is sold and what packages it wants to sell them in.

WOTC just takes a bit off the top for every sale. Putting the content here just makes it sort of semi official D&D approved. And D&DB gets a small slice of every sale though this site.

Not for nothing, but wasn't there a huge hullaballoo not too long ago about a percentage rate between 3rd parties and WotC ... you know, every DMsGuild creator thought they were in their sites, a few much more established 3rd parties told WotC to pound sand, but a few didn't say much of anything....

I think what would advance the understanding the answer to this question is whether the player pack duplicates content in the full books.

If it doesn't, then we know that it's not an equivalent to piecemeal purchasing and we can put this to bed.

If it does, it looks like it is, but we'd have to see if it's not just unique to GFG product(s) or third party stuff.

I don't have any GFG products (and have no intention on buying them, I don't think it's my style beyond maybe Dungeons of Drakkenheim) to check. Someone more into that style could answer. I think, short of an official announcement or explanation, that's the only way to resolve it in the short term (or if we just don't receive equivalents for other products in the future, but that means months of waiting).

Ghostfire Gaming appears to be selling different products on D&D Beyond than they're selling on their own site, so I expect the existence of this is their decision, not Wizards'.

Quote from MidnightPlat >>

I think it should be noted that Ghostfire does put out a player's guide for Grim Hollow with 24 subclasses and other player options including races and lineages and backgrounds.  The physical book with all that is 49.99, not sure how Grim Hollow is represented and at what price point it is in the VTT, digital tool space.   I'll let folks decide whether 14.99 for a quarter of the content, at least insofar as subclasses, is worth it.  When Grim Hollow debuted on the DDB marketplace, "what about the player guide?" was asked.

I do believe Grim Hollow bolted on a lot of sub systems and mechanics to its sort of grim gothic brand of D&D, and that could explain the truncated player offering.  Some of what's in Grim Hollow may not be currently tenable on DDB.  So I do see this as another experiment on handling popular third party in the marketplace (Grim Hollow had been asked for on DDB a lot more than Humblewood, though frankly Humblewood's original book's player options are easier to homebrew than some WotC player options.  Grim Hollow is a bit crunchier).

 On of the Ghostfire employed mods on the Dungeon Dudes Discords said pretty much this when I asked. They have too many unique mechanics running through their stuff for it to be easy to add so instead we're getting the stuff DDB can figure out