Yes, its not much, but it is the beginning of quite a few other maneuvers. You'll need to learn to harrier rightside up, upside down, and knife-edge. Then practice transitioning from one to the other. Eventually you can do high alpha rolls, and then high alpha rolling circles.

Harrier is essential to learn for indoor flying. It will allow you to slow down a plane to keep from hitting walls, or to set-up quickly for another maneuver.

Its just one small piece of the pie.