I think the difference is where the pressure is pushing/pulling from. In the case of priapism gains and even ear gauging, there is a constant pressure from the inside of the circumference pushing out. That pressure over time causes the collagen to become deformed. However, a pump doesn't cause internal pressure. It is basically just pulling the outside of the penis. So no, I don't think it is very effective for quick gains if that's all you're doing. Perhaps getting engorged via internal pressure and then using the pump to hold in that engorged state would be a better route.