well I think it was just a good way to get a beginner to feel the torque, to learn that when you punch one hand forward, you add to the power by pulling opposite shoulder back.
When I was 11, my brother in law taught me an open hand form "八卦拳(Bagua Quan)" (not from the Bagua system) and a pole form "劈手杆 (Pi Shou Gan)". One day I got into a fight. When I asked him after the fight and told him that I didn't know how to use the information from that form "八卦拳(Bagua Quan)", he stopped teaching me and more forms and asked me to train "1 step 3 years" for the next 3 years.
Assume you have trained "1 step 3 punches" all your life everyday. When you get old, which method will you prefer? A, or, B, or both A and B?