School uniforms

Uniforms are used in many private schools in Spain, but, should they also be used in public schools? 
20 years ago, there were uniforms in almost all schools, but, with the habit of buying clothes, the uniform was replaced by ordinary clothes.
Not using uniforms can have advantages or  disadvantages.
The advantages are, obviously, that you can wear whatever you want and you can go to school or high school with comfortable clothes. 
But it also has many disadvantages. In many schools, people judge you according the clothes you are wearing. Many girls and boys can't buy a lot of clothes and it causes feedback from colleagues. 
That is why I think uniforms are necessary in schools and high schools. In Padre Manjón there was a uniform 30 years ago, and I think it would be a fantastic choice that uniforms came back to this high school.