I think it makes the car more consistent. The track gets dusty throughout the run, and the full pins can make the rear a little squirrely when getting on throttle. We have a few switch backs with the current layout, and being able to really get into the throttle for a second or so between corners really helps.

Most of the local tracks are tacky enough that completely bald tires will still give you outstanding forward traction (RCHR, IRH, and RCE).