The only thing it would do on the track is let me lock the brakes and walk away from the car after a DNF
When off they do not impede brake fluid flow in any way and when on they block it 100% so I cant see much use for one on the track. It does need to be reachable for street use because in order to work you have to push in the brake pedal, hod it, then push down on the button before you release the brake pedal again. I had one in a 914 a long time ago and it needs to be as reachable as the e-brake because the button is spring loaded and needs some leverage to manipulate.