Teams is the symptom of a Microsoft that is all over the radar and desperately trying to stay relevant in a world where PCs are heading towards oblivion. Microsoft has failed all of its attempts to enter the portable hardware market (with the sole exception of the latest version of Surface, and that isn't exactly flying off the shelves), has lost control of the browser market and pathetically failed to regain it, and went straight into the wall with its phone attempt.
That is why Microsoft is plugging everything it can into Azure, because that is the only long-term life buoy it has left. Cue the Frankenstein monster that is Teams, a patchwork of anything Microsoft can stitch together and pretend that they had planned it that way.