For a long time, I thought of the blockchain as almost synonymous with cryptocurrencies, so as I saw stuff like “Odyssey” and “lbry” appearing and being “based on the blockchain”, my first thought was that it was another crypto scam. Then, I just got reminded of it and started looking more into it, and it just seemed like regular torrenting. For example, what’s the big innovation separating Odyssey from Peertube, which is also decentralized and also uses P2P? And what part of it does the blockchain really play, that couldn’t be done with regular P2P? More generally, and looking at the futur, does the blockchain offer new possibilities that the fediverse or pre-existing protocols don’t have?
You don’t need blockchain to do ZKP.
You don’t even need ZKP to do these things. Obviously (as you said) there’s a local/state authority who knows this. The library could just ask them about it.
You need a blockchain to revoke proofs. Also, I would like to be able to prove something without notifying an authority of some sort
ZKP and blockchain are for verification without a trusted intermediary and without revealing your identity (or whatever other piece of information you are trying to verify with revealing it). Bringing a local authority into the mix defeats the whole use case.