From my observation the federation is largely split between sides that don't like each other. The main block where the main instance lies is very trigger happy to block entire instances and if a server administrator doesn't follow the group think other server administrators will block you out of "lack of moderation". Account portability exists but requires that you be in good terms with the server admins. Which is fine. Their database and they do what they want but it felt like Reddit with less professional moderators.

On Nostr your account is your signature so there is no such thing as creating an account on someone else's database. You push to multiple relays where people can follow you so even if relay operators ban you there will always be some relay willing to host your stuff.

Others already pointed out there is no blockchain involved other than using the same secp256k1 as Bitcoin for signatures.