The single leg split squat exercise is going to be really good for developing strength and explosiveness in the players legs, but it is also going to help with the stabilizer muscles around the knee area. This is important because it may help to prevent knee related injuries during the course of playing a game. By isolating one leg at a time to work on for this basketball exercise the player is going to be able to strengthen both legs equally.
You may find that the exercise is harder to do with either your right or left leg, and that is because 99% of players have a more dominant leg. Hopefully with though by doing the single leg squats, the player will strengthen their weaker leg. This will translate to being able to finish better off of your weak foot in a basketball game or during your basketball training.