It can actually generate more spin and be more difficult to judge.
As on the forehand, it requires more lifting than a shot off regular underspin. The legs and the whole body are involved in generating the lift while the forearm and wrist impart the spin.
This is the contact point.
Sometimes top players who try to play against defensive player they try to use the backhand loop because the chopper they don't have feeling how much spin they're putting on the backhand than the backhand type spin. This is very important sometimes to use your backhand top spin to play against defense and to get some easy points because normally with the backhand spin you get more rotation than with forehand and this is easier form.