This dribbling drill is going to work on the in and out reverse between the legs combo move, but it is not only going to work on a specific move. It is also going to help the player develop quick hands, as well as soft hands. Combo moves are great for getting past a defender because they use the players defense against themselves. The in and out move is going to bait the defender into sliding over to cut off the move, but as soon as this happens, the player is going to quickly go back reverse between their legs and attack the other direction.
It is important that a player is able to make multiple moves in a row to help breakdown the defender. This will allow them to get an angle to drive past the defender. Basketball drills like this are great because they allow the player to get a lot of repetitions at a specific move in a short period of time, this is important for the players ability to be able master a move.