This was perhaps true in the old days when different styles cherished their secret or trademark moves. It is true that even strange tactics can be used to good effect assuming that the opponent is less experienced and adaptable than the person using it. But, guess what, experienced fighters can adapt so quickly that your secret “Flying Fish Fingers of Death” technique won’t work again if it doesn’t work the first time. I’ve seen this time and time again in sparring with practise swords with a good partner. If your new technique works the first time you use it on an experienced partner; the second time, it won’t work as well and the third time, he will have figured out a counter.
Despite that, I’ll admit as a long-term Yang-style practitioner, I used to believe that it is possible, if one tries hard enough and to sticks to one style of taijiquan, to be able to use only "pure" taiji if called upon to fight someone with skill and experience at fighting. I thought that for many years in my early days but finally realized the hard truth that I wouldn't find the answer to self-defence usage by finding the secret "secrets" of the real Yang-style taijiquan.
This realization came from meeting many taiji practitioners and experts, famous and not-so-famous and observing that those who could defend themselves against competent attacks [all in friendly matches] were the ones who had a great deal of varied martial experience.
Those rarities didn't try to look like a "Taiji-man or woman" when dealing with quality assaults beyond a certain point... that point being, if they were primarily grapplers, that's how they approached an attack; if they were primarily evaders/reactive fighters that's how they approached the attack; if they were primarily strikers, that's how they approached the attack, etc. In all cases, the competent examples who I met could blend with an attack, evade it or confront it as necessary; but in doing so they never looked "shapely" or "stylish" unless the aggressor was being too polite during a demonstration or had little or no experience with un-choreagraphed tactics.
So why train in countless methods and forms in a discipline like Taijiquan if you want to develop some functional skills? I'd like to quote Tim Cartmell at length [with his permission] as he is someone who is truly a rarity in terms of the modern Chinese internal martial arts -- his personal martial skills and experience more than match his considerable ability with words.
"Traditionally, single patterns of movement were learned and repeated over and over until mastered, only then was the next pattern taught. Once the student had mastered an entire sequence of movements individually, the movements were taught in a linked sequence (a ‘set’). The goal of training is to cultivate a kind of ‘whole body’ power. This refers to the ability to generate power with the entire body, making full use of one’s whole body mass in every movement. Power is always generated from “the bottom up, meaning the powerful muscles of the legs and hip serve as the seat of power.
"Using the strength of the relatively weaker arms and upper body is not emphasized. The entire body is held in a state of dynamic relaxation which allows the power of the whole body to flow out of the hands and into the opponent without obstruction. This is described in the Tai Ji Quan Classics as “being rooted in the feet, developed by the legs, directed by the waist transferred through the back and expressed in the hands.”The Tai Ji Quan arts have a variety of two person drills and exercises designed to cultivate a high degree of sensitivity in the practitioner. Using brute force or opposing another’s power with power directly (double weighting) is strictly discouraged. The goal of two person training is to develop sensitivity to the point that one may avoid the opponent’s power and apply one’s own whole body power where the opponent is most vulnerable. One must cultivate the ability to ‘stick to the opponent, smothering the others’ power and destroying their balance."
In the end, style and technique should be clean and crisp in training; in fighting the interaction will look sloppy and chaotic by comparison if both participants have roughly the same skill and experience.
I can't see how it can be otherwise except in a gym with two people of the same style having a friendly match or when the "stylish" individual is head-and-shoulders above his opponent in skill/strength/experience.
Dreaming about finding a master with all the answers — and easy answers, at that — is best left in the martial comics and movies where they belong.
Copyright Michael A. Babin ©2018