Instead of balancing left and right channel of a stereo signal this lets you pan the left and right channel any way you want in the stereo field.

So you have a stereo loop and shaker is on the left and hh is on the right, you want it in mono or dual mono but if you use the balance you loose the hh or the shaker. True stereo panning is the rescue here. ;)

Any other things like left channel to the right channel and right channel to the mid ect. are possible now.