I agree with you completely. About the only disadvantage to a swiss seat is that it takes more time to prepare and adjust than a harness. Come to think of it, my longest rappel (580 feet) was done on a swiss seat - commercial harnesses were not readily available

A curious thing about the rappel belt - that little triangular gizmo used for an attachment point is really quite unnecessary. If you have an adequately strong belt and a proper buckle, just clip around with a carabiner and you are set.