@ricmac Of the issues that @rabble raises the one that I think is the most important to address is:
"Each kind of fediverse server is isolated. You can use a Peertube instance to federate with other Peertubes for video, or Mobilizon for meetup-style events, or Pixelfed for Instagram-like photo sharing, or WriteFreely for blogs. But each of these is isolated. I need a new account on an instance of each of these servers. They all run the same protocol, but they aren’t actually interoperable. You can’t use a single fediverse identity with your profile and followers in Peertube, Mobilizon, WriteFreely, and Pixelfed. You need a totally separate account in each one. With Nostr, you can use dozens of apps all with your same identity, content, and followers."