Windows app should be in the Windows store
Even if there won't be a modern UWP app for Teams, the Win32 app should be available through the Microsoft Store so it is discoverable by Windows 10 users (that's where I looked first, with no luck of course).
This feature is still in the works. There was some adjustments to the overall strategy.
I’ll try to get some additional details and share them with you.
Curtis L. commented
This would also be helpful from the mobile end. As-is, the Win10 mobile app is incredibly limited and when used with Continuum, just resizes to the size of the screen, no additional functionality or improved formatting.
Tatham Oddie commented
Deliver the Windows app as a Win 10 UWP, rather than yet-another .exe file