I don't see how 'flywheel' effect would apply when the socket isn't spinning. If a nut/bolt is stuck, the impact is trying to break it free by 'hammering' against it. But there isn't any rotation yet.
At $61 per socket, I think I'd just buy a bigger impact.
I believe the increased mass at a greater distance from the axis retains some of the energy, thereby amplifying the power of the impact wrench.