It is federated and it has benefits but the UX is garbage for average people and the actual protocol isn't one that'll scale.

You don't need an A+ protocol to get great if your product is good enough / dead simple to use but neither of those things apply to Mastodon, as much as I'd like them to.

I don't see how Mastodon's UX is worse than the one of Twitter, which is good enough, judging by the number of users.