Once you have more experience you can decide to switch to a waist harness. A waist harness offers more freedom of movement. Most kitesurfers use a waist harness when they learned to ride upwind, but for some people a seat harness remains the best option. A seat harness distributes the force of the kite over your legs, but and back which can be better for people that experience back problems. For some disciplines, like long distance and kite racing seat harnesses are also the better option. There is also a harness model from ION which is both a waist harness and seat harness at the same time.