I have been wanting to do this for literally years now, but I don't think I could convince the vast majority of my friends to move onto anything together, let alone Signal. Most of them are non-technical, and it just holds no appeal. Plus, because they would basically just be installing it just to talk to me, they would probably nearly never be online or check their messages, so I'd almost never get to talk to them again.

I basically don't use Facebook (the website), but I am still stuck using their Messenger for communication with most of my friends. That said, Facebook's events system is still the best that I've seen. If it was stand-alone, I would probably delete the rest of FB, and just keep that part. Nothing else on Facebook adds any value to my experience. Nothing you need to be logged in for, at least.