You have a keyring of identities which change in time. The NIP-05 is tied to a domain. The nostr id is tied to a pubkey. The pubkey could be looked up from a number of relays which give a signed profile. But those profiles can also live on domains in .well-known locatations too, the only difference is that relays reply in realtime. You can version control the profile as it evovles stamp it in time, and also track it on a block chain.