Ever played instagib with a low gravity mod in a regular FPS? It can be fun, but the gameplay becomes pretty limited, and I imagine the moon physics being similar in a VR FPS. Maybe projectile weapons only would make it work better, or the fact that hitscan is a lot harder in an HMD than with a monitor.
I always thought that the mitigating factor here would be that you don't have to take big loping leaps, you can also accomplish a fairly earth-like gait, just with fewer steps.
I could also see another way of using it that is similar to the teleport mechanic where you clear an area, make a big jump, and when you land you clear that next area before taking another jump. But it would be an interesting thing, almost like a angry birds pulling the slingshot back thing, where the accuracy of the jump is also put to the test.