If nobody is in the driver’s seat, then it doesn’t matter if the brake pedal exists. If someone does happen to be sitting there, but isn’t paying attention to driving, they might accidentally hit it. And it would be in the way most (hopefully all) of the time.

Sounds like this doesn’t include it, but I think it would be better to have some centrally accessible thing to manually activate the brakes. Then you could do it regardless of where you sat.