Wherever you go in Martial Arts, you will find a multitude of uniforms. Even less traditional styles will have some form of uniform such as a T-shirt with a particular logo or coordinating training suits.
Having a uniform helps with recognition and unity, especially in large events. Uniforms make it easier to identify different schools and organizations. As a business, it's also a great way to get the school's and style's name out there and recognizable. People take note of what sutdents wear and that reflects back on the quality of the school and it's teacher.
But uniforms, especially for traditional schools, holds a lot more information. The style of the uniform is important to identify the origin of the style. Japanese styles wear gi's, the top held together by the belt. Northern Chinese styles wear long sleeves jackets. Southern Chinese styles have short sleeve tops. Muay Thai styles have boxer-like shorts. Korean styles have a solid one-piece top with no openings or buttons in the front. And so on.
In addition, many uniforms carry patches and emblems of the style and school. While not discussed very often, these images have significant meaning to those deeply involved in the style. Most schools will carry on this emblem for years if not centuries, only updating them to signify change within the organization.
While many symbols have similar elements, there is normally meaning behind each component of the elbem which differs from style to style. Many styles, for instance, have dragons depicted in their emblems. But the type of dragon, its position, its posture, what it holds in the claws, and many other subtle characteristics can a lot about a style and a system.
As a student, one should take care of the uniform. It is a sign of respect for the lineage you come from. Never wear ripped or torn uniforms. After each training session, keep the uniform clean and smelling fresh. Respect the uniform as you would respect your teachers as it is a reflection upon them and what they have taught you.