No pumping required .
That is what pumping does, it creates pressure to move the fluid.
..but here is the advantage to a pressure bleeder, specially on an older master ..the piston in the master has a travel pattern and that keeps that part of the master well sealed and clean..but when you pump up the brake pedal to bleed the system, the piston/seals go beyond the normal travel in the master and that is when the seals tear and the dirt gets dislodged from the master walls..none of this happen with a pressure bleeder b/c the seals and piston are not required to move..the pressure from the bleeder do all the fluid movement work..much better and no after bleed system damage...