its main function is for the ollivander's shop and experience. from the ground, it looks like a massive train bridge with a really cool sound effect of trains looming overhead, and it's also used for lighting rigs. but back to its function: you see the stairs towards the bottom of the picture, right? merchandise employees use these stairs to access the wand shop from above and avoid using the big carts to lug around thousands of dollars worth of wands. they reach the store (which is the entire center building) by means of that small cutout on the right flank of the "halfpipe". there's another access point on the left right before it, and that services, i believe, the merch cart.