Rumor has it that a usability consultant died from a heart attack when he saw the first alpha build, but I may misremember the story (or confuse it with the deadly joke by Monty Python).
I'm totally fine with text-based chat, and it had better be implementing an open standard (e.g. USENET news or Jabber).
And it's by no means restricted to Microsoft: many companies use unclear interfaces with non-existant discoverability, sluggish response times, and cryptic menu names like "..." or "+"; and nobody neads multi-row menus at the top to compete for attention with left-side column menus, each of which featuring symbols that lack clarity - since when is one pane of icons not enough?
Well, I use Teams on Linux sometimes because I have a meeting and using a Linux machine at the time.