Footwork is very important in all martial arts and Wing Chun has its own techniques for moving around and especially shifting.
You might wonder if shifting is all that useful in a real scenario, this video shows a way that you can apply it to get your opponent off their center line and take advantage while they can’t counter your attacks.
As important as it is to keep your own center line, you should also look for opportunities to get your opponent off of theirs.
Why are there no prominent wing Chun fighters in the octagon?
There are fighters that know Wing Chun and apply some of the concepts. As with most martial arts, you shouldn’t learn one and expect it to work in real conditions, you should learn a bit of many martial arts and keep what makes sense to you and throw away what doesn’t. It also comes down to how you personally apply your techniques.
Another thing is that lots of Wing Chun moves are either lethal or break bones, so you obviously can’t have that on a legal tournament lol