Signal is the world’s most widely used truly private messaging app, and our cryptographic technologies provide extra layers of privacy beyond the Signal app itself. Since launching in 2013, the Signal Protocol—our end-to-end encryption technology—has become the de facto standard for private commu...
My only problem with XMPP (and a lot of other federated protocols) is really the lack of quality clients. Most of them (especially on systems beyond Android and Linux) don’t really have that good of a UX, or their UI is kind of bland or dated.
It’s something that I hope gets improved eventually. Because having a variety of choices doesn’t mean much if none of the choices feel particularly good.
Want a modern android XMPP client? Try monocles chat. Its UI is kind of modern.
I got mom to use Conversations.
What the other responders said (there are great clients out there, that fit mainstream and niche needs).
Also, it is not a problem of “federated protocols” per se, but of community-led projects. On the downside it may lack consistence and direction, but on the upside you can step in and contribute feedback, tests, documentation, and why not, code :)