You would still want a gaugse to watch it approach the limits, and I would guess that when they are driving they hardly take their hands off the wheel, so you just need space where the thumbs can reach.
Surprisingly enough, before the 2014 season with brake-by-wire, drivers would have to adjust the brake bias (forward vs rear) by moving a little lever down next to their knees. They'd be taking their hands off the wheel all the time.
