Yes it does.
By taking away the distraction of what others are wearing, what you are wearing, students can focus on their academics, rather than their fashion sense.
It helps to foster a sense of pride and unity which turns ones attention to the reason for being at school - learning.
In the long run it is also cheaper and more importantly it provides for a safer campus, as those who should not be there are more easily recognizable; they will not be in uniform.