Well, if you think logically, then it would make sense to cover up her chest. However, if you think of fashion and the type of personality she has, she has to show some skin no matter what. What better skin to show than her chest area, especially since she has a big chest and she likes to flaunt them. Also, this is a fantasy game. Who knows what the temperature is like or what her tolerance is? Maybe she has a super immune system or she doesn't care about the weather. But anyways, the point is not to think about it too much and just enjoy the beauty of the design. But you also have your preferences and that's fine too.