The practical use in games is showing the player a fully 3D environment without the need for a VR headset or red/blue goggles. Imagine playing Crysis of CoD and seeing projectiles and debris fly out of the screen at you. Imagine being able to peek around corners just by tilting your head. It would vastly increase the level of immersion.

In addition, it would also have the potential to make FPS games more athletic, along the lines of DDR and Wii Sports, both of which have become popular as alternatives to the boring old cardio workout. I'll take an hour of dodging bullets in Quake over 30 minutes on an exercise bike any day of the week.