When you move people onto Matrix, what homeserver do you have them use? I've set up a Matrix server for my immediate family and adoption rate has been good so far. I've set up both my parents, and one of my sisters and one of my brothers have signed up, one sibling is being a bit resistant since "I already use a gazillion other chat apps." But, not everyone has a me to set up and maintain a Matrix server, and I'm weary to tell people to just hop onto the main "matrix.org" server since I don't know what kind of experiences there are for people who don't know what they're doing (e.g. Should they put in PII or remain anonymous?)
Mine. Which, at least usually, has working federation...
I don't like the modern internet, and I go out of my way to find workarounds. One of those, currently, is having a physical server colo'd locally to host my internet presence.
Now that Synapse (and Conduit!) support registration tokens, it’s a lot easier to let people you know register on your server, without opening it up to the world.