The following interesting insight was made in another thread:
I think I hold my pole firmly and don't really use the strap as a means of reducing wrist angulation. Has anyone else played with this to see how it affects fore/aft positioning?
Pole straps are important for timing and positioning. In the bumps especially, the pole strap allows you to swing the pole forward without overly angulating the wrist. This puts you forward over your skis allowing you to drive the tips over the top and down the bump (of course by then, you're already swinging the pole forward towards the next bump and the next and the next).