Bitcoin mastodon really was a try-hard effort. There were, IIRC, 3 major pushes to get bitcoiners into mastodon, all of them prompted by Twitter ... being Twitter.
Nostr definitely feels different.
The mastodon efforts only lasted a couple weeks, usually waning as it became apparent that Twitter was not going to purge bitcoin's particular brand of wrongthink.
But nostr feels like an experience that stands on its own. People are sticking around. I want to use it, instead of admitting "It's the best available alternative". There's no algorithm that conditions you to seek or create outrage, which might explain why it's a pretty chill, pleasant experience that is easy to put down.
Perhaps this is timing; I think people are concluding Twitter is directionless and chaotic. There was a lot of optimism that Elon would " fix" Twitter, but at this point It just feels like Elon is just an autocratic operator of a very large, private mastodon instance that can still stomp your account on a whim.
Nostr offers what brought a lot of people to bitcoin -- voice and exit. Accounts cant be stomped, because there are no accounts! Just a private key that you can take to whatever market participant will have you.