The reason is simple. Outside shooting is difficult. A kid has to shoot a few thousand times before gaining a consistent jumper. However, lay-ups can be learned and perfected in no time. Teach your kids to shoot layups before any other skill.
Most kids usually play pretty poorly on defense.
An offensive player who can dribble well will be able to get the ball to the basket for an easy layup with no problems. It will help the team, and your player will take a big step forward in their development. Most importantly, it is easy to do and comes quickly with a little practice. Teach your kids to shoot layups before any other skill. Their confidence will grow and with it the ball player within will emerge.