The Xbox One version of Battlefield 4 will feature head-tracking, Electronic Arts confirmed to Polygon. Specifically, the camera will be used for leaning and peaking, as well as voice commands.
During a demo event, Kinect could locate where a player was seated and then track their head movements, which would correspond to the character being able to lean around corners in-game.
Battlefield 4 developer DICE producer Patrick Bach said in September that the Xbox One version could support head-tracking, though this was not a confirmed feature at the time.
And please spare me the, 'Kinect sucks'. It is optionally used.