Years ago I read about a gel skin cover that would be attached to the outside of the helmet. It would act about the same as the layer of skin/fat that you have on your head. The results is that when something hits your head, it's impact would be moved in all cases except perpendicular. And at perpendicular, would defuse.
This seems to do the same thing, except in two layers. Having a rigid outer shell might have some advantage, but the concept seems to be the same. It mimics the function of the skin on the head and hands so I think it has merit.
The product was much like a gel seat pad that would cover the helmet. It never caught on.