Brian is the design expert, but I see it serving three purposes:what does the cut channel above the graphic do? I see the other board has one as well. Is it a grip for the hand?
1. allows for a much deeper belly (was going for a Velo-esque design here) without having significant weight and thickness through the paipo
2. grip, the ridge is a good area to rest your hand on the deck and push through turns
3. aesthetics, looks intricate and pretty