[Mr. Pink]

One thing that I consider to be a advantage with ball diffs is the friction.
A gear diff basically only has viscous resistance (oil) when the output shafts is spinning at different speed. With a ball diff you have to apply a small amount of differentiated torque before it start to diff. So you basically have a pre defined diff-torque that you can adjust. But this "diff torque" is also depending on the friction between the balls and the input gear (friction between balls and the sides of the holes that holding the balls in place) This friction force is depending on the total input torque going through the diff.

So the more torque you apply with the throttle the more "diff locking" you get.