The obvious benefits are going to be physical. Cycling is one of the best aerobic exercises, and therefore, one of the best for your heart and circulatory system. This means you will much less likely to develop heart-related ailments. Also, as opposed to running(even though I love running and cycling), cycling is easy on your joints, so you can continue to do it for a very long time even if you have naturally deteriorating joints. Cycling is an excellent cross training tool, its a very good way to strengthen a sprinters legs once a week and provide some conditioning.

In cycling, the same thing tends to happen to the same muscles over and over again because the legs are confined to a single motion.