What is the advantage of a folded or convoluted wall in sponges?

Most sponges are immobile creatures and depend on their ability to pump water through their bodies in order to make a living. The advantage, of folded or convoluted walls, is enhanced efficiency for the sponge's ability to gather food and oxygen, and to rid itself of waste. This configuration maximizes the sponge's pumping capacity while, at the same time, slowing the flow of water past each cell. This amazing adaptation allows the sponge to take in more nutrients (pumps more water) while giving it more time (slowing the flow past each cell) to exchange food, oxygen, and waste.