If Matrix is good enough for the German Armed Forces [1], the French government [2], and the German education system [3], I can't think of any reason not to use it :)
Be honest now, there's no way you can honestly claim that Element is a good UI/UX. I'd love it to be the other way around but it's just plain and simply bad. At least on all MacOS combos I've tried - native client as well as web app (Chrome/FF/Safari). And Android. Oh and fuck not being to have different notification schemes for desktop/mobile. I end up having mobile notifications turned off altogether.
So many inconsistencies in the UI. Almost non-existent keyboard navigation. Typing notifications and read receipts on by default (supposed to be a privacy focused chat). Handling unread messages. Lack of threads. I could go on...
I don’t know about Mozilla or Fedora, but have you ever interviewed with Wikimedia? It’s a circus of insanity. The most bizarre corporate culture ever; and the most psychotic receuiter i’ve ever come across. Whatever they choose, I choose the opposite.
...but those are among the three organizations I would trust the least with such a choice.
It would be like recommending a housing strategy implemented in San Francisco, or a public transportation strategy implemented in New York.