My generous interpretation is that he means the GPU is magically energy efficient compared to the CPU. I wouldn't dispute that.
But Apple went down that xPU-taxing path a long time ago when they added the blur to views beneath other views (I don't remember what that was called).
The translucency goes all the way back to the original Aqua interface in Mac OS X. I believe the compositing started getting some GPU acceleration (Quartz Extreme) in Mac OS X 10.2 Jaguar all the way back in 2002.
