Tuning the rear end needs. Our track here is short, twisty right and left, lot of body roll in the corners. Inside tire going up in smoke coming out of one these is pretty common. Some guys use 'throttle over steer' to bring the back end around. A tricky manuever, that virtually requires some kind of taction controlled LS, locker, etc. type rear end.
But what if it were a longer course, with more sweeping corners? An open diff might be fine. Limited slip is most forgiving for overall driving conditions, a 'spool' being the harshest and least forgiving. There are several rear end traction enhancement devices in between.
...and we haven't even opened the gear ratio can of worms depending on WHICH track!
When GM first started using an LS type rear end on their cars (70's I believe) law suits followed almost immediatly. People weren't used to the 'back end' coming around on them. It's much easier for that to happen with an LS type rear. Of course the benefit is greater traction under a wider variety of conditions.