Unless there is a separate GPU contained within that docking station that is extremely unlikely to have the processing power of a PS4/Xbox One and especially so the PS4+ and Xbox One+. That would mean that either some games could not be played while in mobile mode or they will be degraded significantly performance/graphics wise when in mobile mode.
There is just no way they could pack the hardware/cooling/battery into a mobile device.
There is just no way they could pack the hardware/cooling/battery into a mobile device.