If Matix can allow you to appear in Slack, then I would say that's fine. If any info is only visible in Matrix, then I agree — that is not fine. Speeduino has a serious crippling in that there are now 5 different "official" sources for information, all separate. Worse, information to solve an issue or help someone is not cross-linked, so they cannot find the info unless they log-on and search each source. 5 sources, 5 account registrations, 5 logins, 5 searches. Good luck!
Even worse, some of them like Slack have had and lost tens of thousands of informational posts, images, and graphics that now help nobody. To those involved with assisting ongoing development, or spending a lot of time and resources trying to help others, and also find information for ourselves
it is far beyond frustrating and like watching the Great Library of Alexandria burn — every day.
So, I hope you understand that Matrix may be an awesome solution for something, but the initial reaction you may get can be… less than enthusiastic.
That is, unless it simultaneously helps to solve some of the issues stated. If it can, please post that info for us.