Regardless of which Martial Arts style you practice. If you have a good sidekick form, this drill will enable you to have a very strong, stable sidekick. Although the drill itself does not build power directly, it helps quite a lot with the technique. And stability comes, of course, from the supporting leg. And while it looks like you're moving the kicking leg, there's going to be a lot of stability work in the supporting leg, supporting foot and the whole body.