As far as I know they're in the process of setting it up. Desk phones were supposed to disappear this June. Once they make the switch Teams should basically have a dialpad as a regular phone would to let you call any number you like, not just other people with Teams on their computer. My guess is there will be some initial hitches, but I'm not opposed to the idea otherwise. Especially since I'll probably just reroute my work number to my cell phone for simplicity's sake.
I acknowledge at a minimum you're going to need at least one analog phone per building. But an entire VoIP system when you can just have Zoom for the vast majority of your staff?I dunno, this is a pretty standard setup for a VoIP system - plus from what I read Teams is just the next evolution of Skype for Business.
Ever since the lock down, I've been working remote. Everything on either Zoom or Teams. The only people that ever called my desk phone were people trying to sell me something. Course, what will sales calls look like once everyone knows they need to reach me through Teams? (Zoom I receive email invites with links: easier to junk and delete them than dealing with my phone ringing all the time!)