AFAIK on a car with normal viscous LSD, the inner wheel would spin at a lower speed than the outer during a corner. But on a car with racing LSD, both wheel would spin at almost the same speed if not the same.
I tested this theory on my Nissan 180SX (2-way LSD) and a friend's Toyota Estima (normal viscous LSD). When my car gets stuck in the snow, both wheels will turn when I'm gear. On the Estima, only one side will spin, wherelse the other would stay.
In drifting, you would need the wheels to spin at the same speed to get sideways, otherwise your car would just lose control easily, since the wheels will try to balance out and this will result in the car moving in an S line at the exit (of a corner).
For normal road usage, a racing LSD is not required.