Sounds like a perfect way to ghost people. “You send the update on Matrix? Oh, yeah I was stuck arguing with people in Slack all day, I must have missed it.”
One thing that's nice about matrix is that you can select keywords to trigger notifications. Most of the other apps don't have that. So I tell people to say PRIO or PRORITY if their message is really important, so they can force a notification. Any other messages just get looked at when I get around to it and don't notify. If they abuse the priority I simply remove their right to do that.
But none of the other apps seems to be able to do these keywords or (even better) have an option to mark a message as urgent or something.
To the point where sometimes I can't remember on which app I was having which discussion.
6 methods to just keep up with work. I also have at least three ways to reach required documents and meeting notes. I really don't want to jump like a platformer character from point to point to be able to communicate and get things done.
In my personal life, I prefer "1 task, 1 application" model. Communications, one application. Personal information storage? Everything in one place, etc.
Application hopping has a very big mental overhead, and kills my flow. Many colleagues are in the same boat.
It's not Signal, it's any app, account, for any reason.