Thank you for writing this because I'm using Matrix for my engineering conference [0] and I believe in the project. However, no one in our online community (4k members) is willing to switch for good. Virtually no one likes the client's UX at all -- they see it as strictly a downgrade.
So we use Matrix briefly during the conference and then switch back to Discord.
Matrix is a massive upgrade from Discord, and I applaud you for trying to offer people healthy alternatives.
Humans love easy button tasty junk food that put "flavor" or "UX" above all else with no regard for long term consequences. Sometimes those of us that are decision makers have to put responsible healthy options on the table for everyone's benefit even if they don't care about the benefits and also in order to avoid excluding people with higher standards for themselves.
I for one don't accept the terms of service for centralized proprietary chat services like Discord, Slack, etc, and I have stopped attending or participating in communities and conferences that insist on them without at least an IRC or Matrix bridge option. I don't find it ethical to force people to accept privacy and freedom hostile terms of service in order to socialize. It is gross that has become normalized. I hope we look back on these times like when we allowing smoking everywhere in most US restaurants.
Some things matter more than having the absolute best in industry UX. Freedom, privacy, and security are not optional. I would go back to AIM UX before I would give those up. Thankfully Element and other matrix clients have dramatically better UX than that, and with federation, E2EE, message editing, etc.
It is a downgrade from Discord, but from Facebook Messenger, WhatsApp, Google Hangouts and the pile of shit that is Skype it is an upgrade. Element is a bit buggy (just like Skype and Hangouts) but otherwise it is a pretty good client compared to its competitors.
So we use Matrix briefly during the conference and then switch back to Discord.
[0] https://www.handmade-seattle.com