If there is a severe compressor stall, engine failure, etc... that causes the airplane to make a sudden and sharp yaw to one direction, the PF needs full rudder authority to handle the situation. If the other pilot's foot gets in the way because it was resting on them, or even hovering just over them, then that's a safety issue.
For the first few years I was there it was the PF's abort. Right before I upgraded we switched to a Captain's only abort, so that was the policy for my last couple of years there. As a Captain, if the FO was flying, my feet always stayed on the floor. If an abort was necessary, I could quickly get my feet on the brakes without having them resting on the pedals.