What the director is recognizing is the fact that there is a certain expectation for sexiness when women are fighting, which can be delivered through the aesthetic of beautiful, flowing locks… but it’s not exactly utilitarian. One doesn’t have to think too hard to come up with a list of reasons why a woman would want to keep her hair up in a fight, from the fact that it might obscure her vision, to the fact that it might get yanked. And yet we see what Cathy Yan is describing all the time on the big screen.