More Speed Bumps

Just look at the leech and how open it is.
In light stuff, no downhaul, therefore the luff crinkles, and closed leech. ( but not too closed cos that's slow!)
As soon as you pull the downhaul. the luff tension bends the mast, opening the leech ( ie when there's a fair bit more breeze ).
Depending on mast stiffness, sail cut etc, the downhaul is used as the major rig power control.
If the luff is bumpy/crinkly, that is just less important than the control over leech opening.