That's never stopped enterprise IT from rolling out tools to their users.
Teams is free as part of an Office 365 subscription (just like Sharepoint and all the other crap they bundle with it), which is what definitely makes it an existential threat to Slack, because now Slack is competing with Microsoft's very strong Office monopoly.
Teams has some UI issues (please make the chat more compact) but they have a pretty powerful tool for normal users who are already in the Office landscape.
The fact that you can create a group with some channels, add your files there and edit them together, have a wiki, have a (not very good) kanban board etc. makes it a pretty complete experience. Some of the tools they release needs more polish and some tools are by themselves much worse than stand alone competitors but having everything in one is pretty nice.
The best word I have for teams is ‘clusterfuck’. The files which were already spread around different locations, now have one more ___location to be added.
Then there is sharepoint, oh, and onedrive, and they all come in the same package so everyone uses something else.
I don't like Teams much but the calendar integration is really nice. If I get a calendar invite for a meeting via outlook I can tab over to teams and it's right there in the calendar view with a join button. Much easier to keep track of compared to the old way (calendar invite, tab over to slack and find the appropriate channel or group chat to start/join the call)
Teams is free as part of an Office 365 subscription (just like Sharepoint and all the other crap they bundle with it), which is what definitely makes it an existential threat to Slack, because now Slack is competing with Microsoft's very strong Office monopoly.