If you fly a cessna, you certainly want to be able to execute flapless approaches, with those leccy flaps!!! good ole pipers and their mechanical 'ludditeness'
The instructor sounds like a bully, if he was concerned he would have approached you and asked a few polite questions, or talked to your flying instructor. Its poor form to chew out a student without getting all the facts, instructors are human some are good, some not so good.
I practice glide and flapless approcahes even now after my PPL, makes circuit bashing fun!
FK