School uniforms are primarily meant to create identity, to tell one school from another.
A school uniform would generally consist of a range of clothing, much of which is branded.
Those items include a school tie, blazer, trousers, skirts or skorts, shirts and blouses, jerseys etc.
So the look of the uniform depicts the school, from the crest on the school tie or even a school tie with stripes, to the blazer with a badge and possibly even the shirts and blouses.
These will be worn to celebrate or acknowledge the recipient at any given time, normally when the focus is on the particular sport or discipline, for example, a 1st 15 rugby match or an interschools chess tournament.
The recipient has the opportunity to show off their “trophy”, acknowledge their sport or discipline, and promote their school, all of which is done through a school tie, being part of the school uniform!