If you aren’t on the same server, encryption doesn’t always work very well, and you semi-frequently end up with conversations where you can’t read each other’s messages. Id you try get signed out of your app on a given device, you’ll likely lose past conversations. Etc. It’s just… obnoxious.

Eh, I have a serious love-hate relationship with Matrix. For groups its fine. But trying to communicate with individuals on matrix is a major PITA, because of its end-to-end encryption which causes constant issues, IME. It’s great, in theory. But, in practice is just far more of a PITA than its worth.