Voxel models are currently completely useless for anything gaming related that isn't a gimmick because of the amount of extra performance they demand just to do simple stuff like animation and physics. It'll be a real long time before they're as viable for graphics as polygons currently are, and even then it's still more likely that polygon technology will simply evolve further rather than a switch to Voxels happening. They're doomed to be a gimmick.
Gimmicky low-fi applications like using them for a gore system as >>525643
seems to suggest are neat though.