You must also teach how a skill integrates into the whole court environment. Basketball is a sport that has a rapid and constantly changing environment. Players must learn to read and react to many situations based not only on offensive and defensive structure but on circumstances they may not have practiced. Once basic skills are learned, then you must teach them as many environmental decisions as possible base to prepared them to execute in the games. When you deal with human beings you must have some sense of the role that psychology plays on the game.
Psychology is the study of the human mind.
If we were simply robots, coaches wouldn't have to have any knowledge of psychology. However understanding human behavior and things like motivation, anxiety, concentration, and interaction. I will say this however to make a strong point. Studying psychology will not make you the best coach, any more than studying psychology makes you a great clinical psychologist, or studying human anatomy makes you a great doctor. Great coaches understand the role of the mind and how the game of basketball is played.