That does sound like a good system indeed. By extension imagine if you could login to anything using that certificate if it was digital. The problem with digita

That does sound like a good system indeed. By extension imagine if you could login to anything using that certificate if it was digital. The problem with digital data is that it can be copied arbitrarily. NFTs prove authenticity of some data, so now your identity can be provably yours, only a single one can exist, and you can use it to login to things, sign a message that is provably from you etc. Yes NFTs are tradable because they are tokens but you don't have to, and I'd argue an extension to ERC721 which limits NFTs to only a single issuance with a single token would make such a system reasonbly whole.