Let me give an example using punching. It is NOT that hard to learn, we all know you have to coordinate the foot, the legs, hip, waist, shoulder together with the arms to throw a punch like jab and cross. There is NO secrets, most people practice and look very similar. BUT, that's not the only form that works. Some people just punch somewhat differently. Chuck Liddell comes to mind. He is known to be a heavy puncher, here is a video of his knock outs.
The way he punches is a little different. Just doesn't look like the "perfect" punch. He punches with elbow a little wide, but he is not doing a hook punch. He use his shoulder, but not turning as much as a "good" cross punch. BUT, his record said much louder whether he is a good puncher.
This is what I mean about you don't have to do it in the EXACT way. You understand the idea of using the whole body to concentrate and explode at one focused point to deliver the max force. But you have to use the idea and find your most comfortable way of doing it. Maybe you like to stand 15deg off the perfect vertical line, maybe it's more comfortable for you to let your elbow out a little to punch............... It's the idea, the essence of how to punch that is important, not the absolute form. Not like WC that you HAVE to follow the straight form or you are wrong.
Even two people from the same school, same teacher, the way they kick or punch might look different even though they follow the same idea and same teacher.
EDIT:
One more example. Compare side kicks in TKD, Karate and Muaythai
The TKD school I went to, our teacher never said you have to do it "THIS" way. One of my friend who was a good fighter kicked with knee pointing down like Karate. Imagine if the teacher told him you are wrong, you have to chamber with knee pointing up or you are wrong!!!
TCMA school will absolutely tell you you are wrong. That's when I dismiss them all together.
I bet we can have a whole thread just to debate which side kick is better.
This is where I am not interested. I only look at the result, they are all good.