I presume that the gun is pointed in azimuth by differentially driving the treads to rotate the whole tank. That must require a very fine control system for the treads - much finer than that needed for simply steering the tank. I wonder how that works and what the pointing accuracy is. Also, can it bring the gun to bear on a target as fast as a turret can? Rate of fire may be an issue.

Eliminating the turret certainly makes the tank more easily concealable and more difficult to target. However, it means the tank cannot fire on the run - well it can fire but it can't aim so there's no point in firing.