I think the logic for this edge works equally well or better for them. Not a fan of it.

Edit: knowing Alston he wont get the point of what Im saying. Svirfs living underground has nothing to do with gnomes having a high wisdom. The reason it wouldnt work as well or better is because the svirfs have a lower wisdom and intelligence. They wouldnt be cunning or clever enough to do it. Hence the fire giant reference.