Yes, the prevailing wind is definitely the main reason for north-to-south. But don't discount the better views either. Sure you aren't that many feet closer to the ocean, but the views in some of the most scenic sections are completely different. From the west side of the road you're frequently looking right down on the surf crashing into the shore and rocks whereas from the other side of the road all you'd see would be the distant ocean horizon. Much better to have the nicer view continuously as you ride instead of having to periodically stop and cross the road.