I wish they didn't do these tests on a Microsoft-made Surface Book...They should've taken a couple of other popular Windows 10 notebooks and maybe do the tests on those. Who knows how much of this difference is because of Edge itself (which is how well it would work on other notebooks, too), and how much it's the optimization they did for Edge for their own hardware.
Besides, I'm pretty sure lowering the number of frames in an animation (among the other fixes/features they mention) is going to pretty much universally lower power requirements.