I personally find Teams to be an abomination. I asked my wife the other day, who isn't familiar with Slack or Teams, to look at the interfaces and tell me how to IM an individual. She glanced at Slack and pointed to the list of users. She looked at Teams and said "I have no idea". Slack practically invites me to reach out to people. Teams OTOH makes me want to send an email. Now you can add this tracking to the list…
Teams is Skype, but worse. Seriously, it's just reskinned Skype with bolt-ons. You can see "skype" present in the address bar sometimes when you load Teams in a browser. The Teams desktop application (at least on Linux) has references to Skype as well. Teams routinely uses between 200 and 500 MB of memory to run, which makes it the 2nd most memory-intensive program on my computer. On top of that, it doesn't even work…
I regularly get messages come through to Skype mobile but not desktop even when I'm working on my desktop, the mobile app seems to need to crash and restart frequently, it's slow and unreliable responding to incoming calls which often get dropped, when they come to the app at all. Having said that now my organisation has decided to move decisively to teams, it's suddenly becoming unreliable. Maybe having trouble coping with increased usage. Maybe that was the problem with Skype too.