It's on a public ledger, but the data is in a proprietary format. Anyone can read and validate if they want, but equally they could put up their own NFT for the

It's on a public ledger, but the data is in a proprietary format. Anyone can read and validate if they want, but equally they could put up their own NFT for the same thing, and/or choose to not accept the legitimacy of that NFT's publisher. In a way it's proprietary semantics in public data. I'm sure there are open standards in the formats of NFTs that make them less proprietary, but sticking to these is optional, rather than necessitated by participation like the ledger is. Perhaps an analogy... this is an "I got the vaccine" sticker, not a vaccination record. It's publicly visible, yes, and you can check that the sticker looks like it's supposed to, but as a proof of vaccination it's pretty weak as anyone can create them and hand them out on their own terms.