It's the same with other Microsoft products. Like someone else said, it doesn't matter how bad they are, money streams are basically guaranteed.
It's weird how their software almost feels like shareware or debian packages lurking in the repos unchanged for 10 years, just with ads and unresponsive UI.
Students and teachers really have no interest in being informed on the bottom of the screen that it's currently raining (we have actual windows for that), nor do we care that Ethereum's Ether fell by 10% in value this day.
Such things make no sense in an educational setting. Moreover even browsing the web when the teacher wants to show us some JS animation on a website (you know, such website that doesn't get updated, yet works, it's path starts with a tilde, and is only served via plaintext http) is uncomfortable, as Edge browser starts up with a screen filled with ads and random news articles about the war in Ukraine or political situation in the US.
I went quite off course, but Teams is no different. As soon as the teacher logs in to the computer, Teams is starting to launch. Why? It would be somewhat okay if it just launched in the background, but no, after 20 seconds a Teams window opens, wastes 5 seconds of lecture time, because it doesn't immediately have the Close button drawn.
Maybe theese are all just issues our IT team could solve, but given the immense amount of money siphoned into MS both by the school and the country's educational ministry, some reasonable defaults could be expected.