Our instructor emphasizes that the highest evidence of a practitioner’s comprehension of Wing Chun is the ability to effectively communicate it to others. Obviously, skill in application (fighting) is the ultimate goal. Actual fighting ability is certainly the primary reason for training in the fascinating art of Wing Chun Kung Fu.
But no matter who you are, from Bruce Lee to "Paul the Pugilist" to "Mr./Ms. Mild-mannered," you will spend much, much more time learning and teaching than you ever will fighting. Therefore the practical goal that will provide the surest path to the ultimate goal (fighting skill) is becoming the best teacher possible.
Teaching is an art in and of itself, and the better your instructor is at it, the better you will be at not only learning the technical aspect of Wing Chun, but also the art of how to teach it most effectively. Consequently, the better your teaching skill and the more you teach, the better you will comprehend the art as you both apply it (fighting, if necessary) and pass it on to the next generation.