was actually one of the scenarios which I thought about before posting, but I was more interested in the technical aspect, so I left that out.
Offering more options for the player is always a good thing (in my opinion).
But one thing to consider is that your level has to work with and without VXGI. Maybe offer LPV or 's AHR as alternative? You could just turn off VXGI, but that would heavily impact the appearance of maps (depending on how they are setup).
At least is what I imagine, would be nice to get the perspective of a level designer.