Yes, making them look cool and mysterious is one of reasons why most of musicians preferring sunglasses. The sunglasses will bring them the cool and mysterious appearance which is always regarded as the accessories to improve the looks. On the other hand, fashion can be another reason, for there are many different styles of sunglasses, which will make them seem to be unique as well. What's more, by wearing sunglasses, it will protect their eyes from the strong lights even in the room. By the way, if they go outside, sunglasses can just protect their eyes from sunlight and uv rays. Therefore, no wonder why most of musicians prefer sunglasses.