Even the few people who complained that they wouldn't use it because there wasn't a phone number to call for telecons were overcome when we told them to just install the app and join the conference that way.
For internal work, it's actually been a lifesaver. Webex and other solutions have failed to hold up under the strain while Teams has more or less just kept marching on.
I have a feeling as this goes on for the next few months Teams users will not go back to the fractured fragile mess of other apps we tried to get along with before hand.
Hell, there's even a halfway decent Kanban built in.