i am on nostr because it is the only truly decentralized social network.
1. it give you a keypair to be in charge instead of email/password managed by instance admins, where they are part of the name others know you by and, where they theoretically could impersonate or censor you.
2. you always have to choose one instance
in relay based your signing keypair owned by you is your account and you can use any relay (=instance) interchangably and even at the same time