Fighting is not an efficient process. Trying to find efficiency in fighting is like digging in mud during a rainstorm trying to find dry soil. It has a low probability of success.
Effectiveness in fighting, however, is always worth seeking.
Effective fighting is a function of efficient training and efficient learning should be the primary desired outcome of practicing martial arts. Cultivate efficiency in training; seek effectiveness in fighting. This is an authentic approach to both and will improve your outcomes in each.
It is unfortunate, then, that the majority reverses this truth, by design or ineptitude, instead focusing on demonstrating effectiveness to students and encouraging efficiency when tested in fighting. Fighting is ugly, punctuated by beautiful moments of execution amidst the chaotic nature of the battle.
Demonstrating an effective technique to students makes the presenter seem very skilled, but does nothing to enhance the skills of the presentees if the instructor's delivery is haphazard or inefficient; worse, it facilitates illusory thinking and encourages esoteric interpretations of what is ultimately a simple process of desired versus undesired outcomes for the learner.
Some of the weakest kicks I have personally experienced came from fighters who were award winning board breakers in their chosen art. Breaking a board may look effective to students and the kick might appear incredibly efficient in sparring, but the former is more a product of efficiency and the latter is simply not true.
Personally, I do not even know if I can break a board with a kick...but I can provide references from people who do not ever want to be kicked by me again if they can help it. My kicks might not look efficient, but I know they are effective. I have social proof that allows me to state that. I also have social proof from some coaches who hate the appearance of my kicks, though they are willing to concede the effectiveness of them.
Can't win 'em all and can't please everyone, I suppose. The key is to not get swallowed up by ugly lies. You can be efficient but not effective; as a result, you will likely lose. You can be effective but not efficient; as a result, you will likely win.
It is a beautiful truth if you can accept it.