I can take or leave them as a thing. Taught in range of uniforms and non uniform schools.
I've worked in a non uniform school ans loved it. There was a dress code and students got on with it. Behaviour was amazing (but then that was instilled into the pupils by home and school - none of this 'well I told my DC to ignore X Y Z and I'm proud of them for arguing because teachers need reminding they don't get blind obedience'
)
I don't think it would work as a norm in UK schools though because the culture is bizarre. So school say 'plain black school shoes' and some parents decide 'fuck being a responsible adult. I'll buy a pair of black trainers that cost £80 with branding on the side and then whine when school tell me they aren't school shoes. Then I'll get my sadface on social media and ask other bafoons if they think a pair of sodding trainers are school shoes.'.
Or school say 'natural hair colours only' and then someone turns up with purple in their hair and is all angry in the local press because the school is ruining their child's education.
In short, there's a reasonable chunk of absolute idiots who think that even the simplest rule doesn't apply to them.
Ideally for me there would be a simple uniform, easy to source, affordable with a range of options for pupils.