Federation is no panacea either, it's also a privacy tradeoff, since the communication metadata is distributed across multiple servers operated by different people (unless you only communicate with people on the same homeserver that hosts your own account).

It's just something about Matrix. I don't know what it is. I've never opened the app after logging in.

It has a good UX which is rare for open source apps. It seems to be based around a decent community. But I don't know why I don't use it.

We should, but it is much harder to get my family and friends to use Matrix.