limited gun depression on a tank is something an enemy can take advantage of. Several russian tanks have this problem too.
For example the russian tank is coming over the hill, but can only fire after exposing their underside.
alternatively A german Leo 2 tank with good gun depression can shoot downwards, and remain hull down, protecting half their body. Bad gun depression means the tank has to expose more of itself to shoot.
This is because the turret roof stops the breech (loading part) from going up. Like a see-saw. Like this. In thıs picture you have good depression. You can engage enemy target without expose your frontal armour or your lower plate.
You should start play World of Tanks bro