MS Teams didn't have support until a month ago or so for replying to messages... It is obvious that MS Teams rise in popularity piggybacks on popularity of MS Office and MS Windows. Rise in popularity of product that lacks such basic functionality is a proof. I work in a company that uses Office 365 and MS Teams. Company needs to battle some MS Teams outage or other high-severity problem ever two months or so...
I fully support all companies who sue them, it simply isn't fair if M$ can integrate apps into Windows, while third parties can not obviously. It's the same as with Win Defender, eventhough I do think it's a pretty good AV. The playfield has to be leveled.