I’ve never used the knobs and triggers on my VR controller for anything beyond game selection. In fact, I think Oculus would do better just to put out additional simplified controllers meant for fitness gaming.
Nothing wrong with rhythm games if they can help you drop 40 pounds.
The space problem is easy to solve with....space. A VR gym setup could easily solve it by putting you in a racket court with an appropriate guardian, and then let the VR system do the rest. Otherwise we will have to wait for Omni directional treadmill tech to get better.