As I understand it, Material (and Microsoft's Metro, interestingly) aims to be better on battery compared to predecessors if only because it's a simpler UI with

As I understand it, Material (and Microsoft's Metro, interestingly) aims to be better on battery compared to predecessors if only because it's a simpler UI with larger plain blocks of color, minimal decorations, and far fewer "expensive" effects like gradients or translucence\transparency. That doesn't mean said wins aren't immediately consumed by other parts of the system, even other parts of Material UI widgetry. Regardless, the simpler flatter design frees up some resources (battery, ultimately) which can then be used for other things, like smooth animations and transitions.