Surfboards for Speed
This brings me to surf riding in general and riding surfboards specifically. Surfboards on kites are great for two aspects of riding; going fast, and surf riding. Surf boards for kiting give you a lot of traction and more freeboard than a twin-tip. Anyone who has blasted a twintip board fast in choppy seas knows how hard it is to control. When you ride a surfboard you're actually more toward the rear of the board so the front of the board takes the movement from the chop. This combined with the increased traction from the longer set of 3 or 4 surf fins make it perfect for going fast in any conditions. Besides actually surfing, going as fast as I can while transitioning from heal to toe side and back is one of my favorite things to do on a surfboard.
Surfboards for Light Wind
Because of the reward position of the rider on a surfboard it can be challenging for new surf riders to make it back up wind. You have to get used to keeping the board flat on the water instead of digging an edge in when working the board upwind. Once you're used to it, a surfboard can also be a lightwind weapon because of its extra displacement. A large surfboard really makes a difference in light surf conditions because it is easier to keep an edge in the turbulent water.
Surfing and in the Surf
It wasn't until 2009 or so when I met Chris that he convinced me to actual pull the straps off my surfboard and start actually 'surfing' it. We still laugh about how bad I was at kitesurfing at the start, "how can someone so good at kiteboarding be so terrible on the surfboard!" Well, I eventually got it figured out and never looked back. In fact when I broke the world record for distance travelled on a kiteboard in 2010 it was on a surfboard. The surfboard is designed for the surf and great for the gulf coast. Its larger volume helps make up for lost buoyancy in turbulent water and the larger fins help keep traction even when in whitewater and surf to help riders cut upwind. Both of these factors also help with the side current we always get in the summer which can feel like a treadmill on the water.
Overall surfboards can be a great addition to your kiteboarding quiver. They're really good for learning toeside riding as the heal to toe transition is very fluid because of the rounded rails. They are also great for learning to jibe (switch) your feet while transitioning from one direction to another. Even if a surfboard isn't you're "everyday ride" it is still something you should try and learn as will increase your overall flexibilty and range as a rider.