Only Nostr has a solution for actually owning your identity, your "account."

The federation approach used by Mastodon and the wider "fediverse" (ActivityPub) as well as Bluesky et al may distribute the central parties, but they still exist.

Your instance admin can simply delete your account at any time. Even if you self-host, your content can be taken down by your host or ISP at any time.

This is why federation isn't censorship resistant. If you look at how the Mastodon devs talk, this is no doubt a feature not a bug in their eyes.

While PGP already solved owning your identity, it still relied on the assumption people would use centralised services (email) and it's still to this day virtually unusable for most people.

By combining a truly decentralised network with cryptographic proofs, Nostr has finally created decentralised encrypted communication and identity verification that can be used by anyone with a smartphone without requiring KYC like Twitter and Meta.