A loose grip helps alot with draw.
Yes, and no
Yes, a lose wrist allows the player to deliver a cue to a specific point on CB allowing the shaft to do the work
However::
One could hold onto the butt with a extremely tight grip and if the cue tip hits the CB at the same speed and position as above, the grip does not mater because the physics of impact transpire faster than the speed of sound travels down the shaft to where you are gripping. So how the cue is gripped is absolutely immaterial.