In my plebeian opinion: Nostr is just using a different form of login than a User generated ID and password combo that a given company holds an matches to your profile. However, the pubkey is stored on the relays unless they purge it and everything is encrypted unless you have the private key to unencrypt it. You can’t take that identity with you to say Twitter or your bank and say, this is who I am because I can prove it with key signatures (yet, maybe one day it will be there) and not actually share any private data.
DIDs are identities built using cryptography that you “custody” and can control who has access to it for verification/marketing/login etc. that contains private info. You can revoke access at any time since you control it and take it to anyone using that protocol, but like a govt issued ID card, it says you are who you say you are but with the added benefit of not having to reveal private info unless you want to.
Very similar but also different. NIP-05 is a step towards maybe some portable identities but don’t think it’s as flushed as what #[2] and team are attempting at TBD.
Mike/ #[3] am I sort of on track with my understanding?