Let's think about it. The whole point of a blockchain is to establish decentralized consensus regarding a chain of transactions. Bitcoin and the like do so by wasting a ridiculous amount of energy proof-of-work-ing a hash pace that would thwart any attempted 51% attack. Others use proof of stake that effectively tends to put all control into the hands of an oligarchy of early adopters and/or old world capitalists.
But we could do so much better. Imagine if everyone was capable of use public key cryptography while keeping their own identity-linked private key properly private. No more Sybil attacks. No need for PoW or PoS shenanigans. You'd simply only need a certain number/threshold of transparently unique _real_ individuals to sign off on a block for consensus to arise naturally.
I've always believed properly implemented PKC could be key to a truer form of democracy than the world has seen so far. Then again, I'm not sure I have enough faith in humanity for this to actually ever happen.
There also seems to be other blockchains to offer identity management, albeit no additional UBI aspect, so then how does Worldcoin beat out the other blockchains offering the same service? It's not clear to me but I agree that it's good that people are trying.