Why turn off traction control? Good question. There are some instances when traction control will not be helpful. Swimming through mud or deep snow when cleaning tire tread blocks by spinning tires is needed and or when momentum needs to maintained in order to get to the other side. These are the normal type cases I can imagine turning off traction control. Why Mr.T didn't make a button to disable traction control available from the factory, I don't know. Maybe someone can hazard a guess. I will say that I have seen enough YouTube videos of ATrac equipped Cruisers to believe they are decent for a lot of off road conditions. It's a option to have, but I'd like to be able to turn it off.
Other cases to disable VSC/ATrac are cases when the system isn't working properly. Several of the cases studies I read where the traction control caused a problem were in every day on road driving conditions. The malfunctioning, or perhaps over sensitive, traction control resulted in dangerous situations, stopping in front of oncoming traffic. Being able to quickly disable the system and move the vehicle normally would be a big advantage.
I want to be in control of the car as much as possible. In today's world of drive by wire, this is less and less a possibility, but I at least like the illusion. A hard cutoff gives me that security blanket. I personally like ABS, especially on road in slick conditions. I try not to rely on ABS, but it's good to have there in backup, kind of like the intent with VSC and ATrac being on by default. Further, temporarily loosing ABS with the flip of a switch is acceptable I guess. Driving around in the winter with a gimpy VSC/ATrac turned off is not as cool though.
$800 to repair the traction control system is spendy. Does your ABS work, or is that a casualty of whatever is at fault as well?