One key difference is friction. With wheels there is continuous contact with the substrate, which means continuous friction and thus energy loss. Since this rob

One key difference is friction. With wheels there is continuous contact with the substrate, which means continuous friction and thus energy loss. Since this robot has an aerial phase, this should be considered an advancement towards the energy efficiency of most land animals who only* lose energy due to friction when in contact with a substrate. Edit: *not factoring wind resistance, which is present regardless of mode of locomotion.