For one, Zoom did just work. (At least as a participant, rather than an organizer.) I tried it out, and it immediately worked. It did what all of us were expecting, with no fuss.
I also tried MS Teams. It seems designed with a different philosophy: that you use the software to do many different things, and you want them all integrated. (For example, it posted my meetings automatically to my Outlook calendar. I had never used this calendar before, and was only dimly aware that it existed.)
Moreover, it seems that the expected setup is a bunch of people, all at the same workplace, who communicate with each other consistently. My needs are different, with wildly disparate use cases: a departmental meeting; classes to teach; an online conference (https://www.daniellitt.com/agonize/); an online social gathering. Many of the people with whom I communicate don't work for the same employer. And I don't want to configure all of these "teams" in advance.
That said, I tried to get MS Teams up and running, to teach my class. This involved multiple emails back and forth to our tech support (it seems that I can't set up a "team" myself; I have to ask IT to do it for me). It didn't have its own whiteboard functionality so I had to download and run some separate software.
And, then, in the end... it didn't work. I was trying to teach a class, but my students couldn't see what I was doing. I had no idea why.