I like to do them just for fun and exercise and skill development, but not for defense, or in sparring. However, learning kicks like the jump spin side kick has helped me to develop a spin side kick that isn't a jump kick, but a very fast switching foot kick, in which both feet leave the ground at the same time. However, it is not a jump. As far as the height of jump kicks go, front kicks and crescents you can get higher than the ground variations, because of the jumping, but for side kicks, it is tougher to do.