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 any more forms and asked me to train "1 step 3 punches" for the next 3 years. Since then "1 step 3 punches" is always part of my daily training.
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? I assume this should apply to all the other training as well. There is a slight gap between the TCMA training and the real combat. During the beginner stage, you may want to separate both training, one for body method, and one for combat. But do you truly want to treat yourself as beginner when you are 80 years old?