Great ball handlers are able to move the basketball from hand to hand quickly and with ease. They also have really light feet that are able to push off and change direction quickly - as well as stop quickly. This comes from being comfortable with the basketball and also playing from a low athletic stance.
The behind the back rhythm dribbling drill is going to specifically work on the behind the back move, but it is also going to help the player really learn to play low and develop quick feet as they handle the basketball. It is a great basketball drill to work on ball handling on the move, and it will also allow you to get a lot of repetitions at a specific move in a short period of time.