I know that we can create workarounds and yes for some interface (even intellectually) it is quite fun to create those dynamical 3D interfaces
But… you’re missing the point 
The UE team has developed the UMG so that we can easily create even complex UI without having to spend too much time reinventing the wheel.
It would be a complete nonsense to have developed UMG for that purpose and that it would not be compatible for VR. Don’t forget that many of us are developing applications that are compatible both in VR and non VR mode… and we won’t start creating two different UI for each mode. And yes, some UI can be pretty complex. For instance… If you plan to create mini games inside your big project (ex: mass effect security override) or if you are creating a level up experience graph (like in… well every rpg-like now). Those UI can rapidly become complex and UMG is perfect for that.
Anyhow UMG creates UI. It is its sole purpose. The only thing that we are asking is that it works also in VR mode. That’s it.
And for that, fixing some “simple” issue would help a lot:
questions/238696/error-in-ue-480-preview-4-when-hud-and-vr-preview.html
And then after, it is true that better collision detection with motion controller would be great !