Perhaps, but I was under the impression GPUs have greater power efficiency than general purpose processors at least some of them have physics support (collisions, etc.) these days. Since the problems are primarily spatial, shouldn't even GPUs without dedicated collision detection in hardware easily support reasonable speed prediction? (eg. Simple CSG[1]-style union?) Is this purely about power consumption, as suggested in the article? (Surely a low-res approach with area-of-interest identification for potential collisions to suggest higher-res calculation could speed things up, in the same way "I've got a bad feeling about this" makes us think twice? Perhaps someone with more knowledge of the algorithms could clarify?)

[1] https://en.wikipedia.org/wiki/Constructive_solid_geometry