Web3 as it is is impotent and useless. Yeah, that makes it harmless, but the idea behind it isn't.
The idea behind web3 is that everything lives "on chain" (the same way the idea of the Internet to some was that everything is "online"). This is not just a whimsical dream but a vital necessity for most of its promises to even function. Listen to crypto enthusiasts and you'll hear many scenarios which only work if this is already the case.
"Smart contracts" are useless for anything "off chain" because they can only interact within the chain. You can set up a smart contract to grant royalties off the trade of an NFT, sure, but if you mint an NFT of your book to do that you can literally still sell copies of that book "off chain" without triggering the contract (so you still need the entire legal apparatus of the centralized state dealing in fiat currency, which NFTs and crypto and smart contracts were supposed to replace).
You can see this play out in the (poor and thus cheap to invest in) African countries crypto enthusiasts have been trying to use as lab rats: universities issue their degrees "on chain", land ownership is tracked "on chain", and so on. If all legal documents and claims are replaced by tokens and smart contracts, you can circumvent laws because what's the point of having a legal claim if you can't enforce it because everything runs on the chain and the chain disagrees with your claim?
Even the enthusiasts of course forget to talk about how this makes every person incredibly transparent (no need to "dox" strangers, you can just track their transaction history and literally inspect their wallet to find out everything there is to know about them) and how it turns identity theft from an annoyance to something irreversible (because to the chain, every owner is the rightful owner) that can happen to you as easily as accidentally leaking your Facebook password. Yes, I know about tumblers but if you have to resort to money laundering tools to recreate any semblence of privacy I hope I don't need to spell out how this seems to be more about money laundering than privacy.
And this doesn't even go into how all the fabulous claims about NFTs in games are little more than microtransactions, lootboxes and DLC, how "play to earn" just replaces game mechanics with grind (or at best encourages literal ponzi schemes of renting out your account to allow other people to fight over scraps until the currency becomes worthless) and how none of the technologies involved are "new" or offer any interesting solutions to problems that actually exist outside crypto itself.
Oh, and of course on top of that every single crypto project is either a ponzi scheme (or pyramid scheme, or any of the dozens of variants of scams that are legally neither of those because of technical details but still function the exact same way) or a "rugpull" waiting to happen.