Sliding Window Advantages
Sliding windows tend to be most popular for bedrooms and areas with lots of exposure to afternoon breezes. They offer lots of light and are a great option for larger and more vertical window openings. (They are rarely used for taller, more horizontal window openings.)
One reason why they offer more light into a room is that they typically use a more narrow frame than a single or double hung and thus offer more glass area which allows more light in.