Dynamic lighting in general is not a good fit for VR - you need GPU time to be as low as possible.
If you sample it on the surface of a shadow casting object, you will get more or less 0 (the distance field is fairly low res so there’s error). However if you disable bAffectsDistanceFieldLighting on that mesh, you will get the distance to other casters, regardless of whether the material is opaque or translucent. So in general, it’s most useful on translucent surfaces as they weren’t going to affect distance field lighting anyway.
The only problem with this is the low res nature of the global distance field. You can do fadeouts over a few meters, but not over a few centimeters.
In tests in larger maps I’ve noticed that using the distance field particle collision for snow will show some artifacts - the distance field is low res and rounds out corners, so often the snow will fall through instead of sitting above the surface. We might be able to improve this in the future as there are much higher resolution per-object distance fields that can be used.