Why a 60Hz camera and not a camera with a faster refresh rate (120Hz)

Oculus is particularly concerned about latency, if they are using a 60Hz camera for DK2 it's because a higher frequency is probably not needed.

They don't even track position at each frame because it's too costly, so a higher refresh rate wouldn't bring anything more. They rely on iterative pose estimation and a high frequency IMU to get good precision (0.05mm) and low latency (~20ms avg. with timewarp).

See here for a detailed explanation about how positional tracking is implemented in the SDK : https://www.youtube.com/watch?v=dxbh-TM5yNc#t=2162