The ability for the screen to move further from the user's eye means that it is healthier.

It allows users to naturally focus their eye in the device.

One of the drawbacks of current HMD systems is that if a virtual object appears far or close, your eyes are always focused at the same rate. 

Even when you use a laptop or mobile phone for extended periods of time, you should take a break to look out of the window and focus on something 20 meters away to exercise your visual focus.

Uploaded by Oculus on 2018-05-24.

Notes taken on a mobile device. Pardon any auto-corrections or incorrection.