Because of the customs in China, girls in China are rather conservative, so they don't want to wear cool vests or suspenders.

Mainly the social atmosphere. Most people can't accept it. Girls don't want to be judged and pointed, so they don't wear them often. On the one hand, it is too exposed, on the other hand, it is too tight.

The sling, the whole shoulder, including a part of the chest and back, is bare, and the miniskirt is exposed below the thigh, which makes it cool when a small wind blows.