Its worth it especially if you are a new player or an oldster that is trying to bring in new players.  The tools take away most of the complication of character creation and are well laid out for playing the game.

If you are only playing one game right now you can buy just what you need for your character it lowers the price of the larger product and lets you try it out for less.

Example: you want to play a wizard you can buy the subclass you want and the spells from players handbook (probably cost about $10)  you can play your character and if you decide you want to keep playing buy the players handbook and its $10 cheaper.

The big advantage to the books is you have them forever. If wizards one day decides to stop licensing to dndbeyond, or a new edition comes out and you don’t like it, you can keep using your books. 
Dndbeyond is a great resource and worth it, I think. Just something to consider is that you don’t actually “own” the book here. You just, basically, buy the right to use it. 

DnD Beyond will likely be more useful, just for the character builder alone.

The only reason I have the books + DnD Beyond copies is because I simply love books. But they are less convenient and portable than having the content online. The only advantage of the books (for someone that doesn't cherish physical copies as much as I do) is the fact that you don't rely on internet to access info.

If you're very new, I'd say don't buy books yet either way. See what you can borrow from your library (even through interlibrary loan if they don't have it in their own catalog) or from the DM or other players for free before you invest money in it. Once you're sure you really do like D&D specifically (vs other TTRPG systems) and you're playing with a group that isn't going to dissolve in an instant, then look at getting a book or two. The Basic Rules are already free, and you can use the homebrew tools to recreate things from the books for free also.

It's down to personal preferences. 

Positives for DDB:

1. All "contained" in a tablet, phone, whatever. Much easier to store, carry, etc.
2. You can't break it or ruin it.
3. You can have as many copies as you have electronic devices.
4. Character creator brings all the content together. With my books, I have most of my character stuff in the PHB, then one race in a different book. Just...Great.
5. You can buy it piecemeal get what you need as you need it.
6. If you come across an encounter in a published adventure as a DM, you can just click on a creature and get its stat block up. That's much easier than having to look it up in whatever book it is.
7. It's cheaper. 

For physical:

1. I find it easier to navigate.
2. If you look after it and have no accidents, it's yours forever. Don't ever have to worry that a licence will be withdrawn or a company go bust and you'll lose your stuff.
3. You can flick back and forth. I found that it's much easier to quickly reference an integrated map. In the app, you have to navigate through several menus if there is no link on the page you're on - with physical, you can just keep your pinky to keep your page.
4. It's easy to share a map that all can see and discuss plans etc.
5. It has resale value.
6. No stress about battery life, your phone being on the blink, etc.
7. It looks cool.

If you are worried about not being able to access your digital materials, you can always save the webpages as HTML files, and have back ups of them on not just your computer, but also email and social media too, so it is very difficult to lose them in my opinion.

As for which I prefer, I lean towards Beyond due to the convenience the tools provide.

I wouldn't have gone digital if not for covid and the ensuing push for distanced online games. Even with the experience of the last two years I still wouldn't go digital if my hand wasn't forced (if the digital sources were properly searchable .pdfs I could annotate it'd be different, but WotC isn't going to budge on that). That said, there are definitely benefits to the digital side as well and I think the price is fair, so if that's the way the cookie crumbles for you then DDB is "worth it". I current double up, but I understand that's not a sound financial decision for everyone - I certainly wouldn't have done that a decade or two ago either.

I should point out that this is on the D&D Beyond forums, so it's likely we'll all be swaying toward D&DB being favourable, short or long term. Caveat emptor. I also strongly advise that you don't buy any books yourself. D&D's cheap, but so's free. Use the resources of other players, or suggest everyone playing contribute a portion of the cost for shared resources.

The case for D&D Beyond is it's terribly convenient, and being digital, this can be to its detriment. More on that later. The character creator is a fantastical tool, and whilst limited with six characters to play around with, six characters should be enough to choose from if you're brand new to D&D. A shame the limit doesn't go up given there's more than six classes, but again, more on that later. The books aren't great to look at on mobile devices, but they're OK on PC screens. Combine the contents of the books being added straight into your D&DB character creator, and you save so much time cross-examining your books and character sheet, and save time writing/typing all the class/race features in by hand.

The cases against D&D Beyond are that I don't think it does a good job of teaching you how to build a character because the convenience is so great, and unless you've made a lot of characters the lessons might not sink in. It's why I have a horrible time writing my own character manually, for those rare occassions I might not be using D&D Beyond. "How is spell DC calculated again," and "have I missed any subclass features" are questions I've had to ask myself numerous times throughout that process. I'll be honest, without D&D Beyond my habitual creating of characters purely for funsies would be over in an instant. There's also the matter, as other users have said before, that you can lose access to these tools at any time, intended or not by Fandom/Wizards of the Coast. Licenses expire and servers can have power outages, but books will only expire to the elements. Even then, there's the matter of being able to get copies through printing services such as DriveThruRPG, used copies, local libraries, or any brand new ones that might still not have shifted yet. Finally, as someone put it far more eloquently than I will, the D&D Beyond Hero subscription is essentially what makes a lacking site good, not a good site great. Without the subscription the site is subpar, regardless of how little the sub costs (and honestly, I'm fine with paying ~£4.20 per month for what I get out of it. Call me part of the problem if you so wish.) Finally, with D&D Beyond there's added eye strain if you're already playing a virtual tabletop (VTT). I relish the chance to look in my physical PHB for something because of the eye fatigue that comes with watching a screen for everything, be it a mobile device or desktop screen.

Probably also worth pointing out that if your group has books on D&D beyond, then all it takes it one person having the master tier subscription and the whole group can share those books for reading on D&D beyond and for character creation.  That's exactly what my group has done