Realistically, what downsides would there be if first-world governments began banning spray paint? It is almost always used for criminal purposes nowadays.
You'd significantly decrease graffiti and with it the vandalism it entails. You'd also remove a source of intoxication for drug addicts chasing a high. I legitimately cannot think of a reason anyone would need canned spray paint other than to cause themselves or others trouble. Those who customize cars don't use cans, but their own high-grade applicators. Workmen might be slightly deprived, but we have shit like VR or UV/road paint if they badly need to know where to drill.
I'm happy to tolerate graffiti knowing we have easy access to spray paint to deal with such issues.
Graffiti is the least of my worries.
Also, I admire some graffiti, especially the spray-painted stencil graffiti which is almost exclusively anti-zionist: walk through your capitol city and look behind street signs and you'll likely see such stencil art "graffiti".
I sketched some simple stencil designs during the Covid lockdowns because I was so enraged by social media censorship and wasn't sure if things were going to get worse and make all social media goyshot discussions vanish. Fortunately it didn't get that bad and social media activism remained the best way to reach people.
Stupid kids have a right to feel angry and hopeless as usury and inflation debt slaves under ZOG, even if they don't understand the cause.
Just because something is illegal doesn't make it wrong.
I like knowing I can use spray paint to write political messages on overpasses if the need arose.
I'm also terrified of any laws against any paint because mixing black paint with oil (any oil will do such as used cooking oil) and filling water balloons with that mixture is a profoundly effective defnse against government riot police and their vehicles:
* The black oily liquid makes vehnicles useless if you get it splashed on their windscreen, especially if they're attempting not to rundown their teammates. Burst a balloon against their rear window and the vehicle because unusable. Windscreen wipers only make it worse.
* Splashing riot police makes their transparent shields opaque and makes their gloves or hands too oily to hold the shield or operate a firearm. They also wouldn't even risk firing rubber bullets or smoke grenades when their teammates are covered with unknown oily stuff.
To be clear: This is just something I read and I don't condone such illegal behavior.
I also don't condone carrying bricks in your backpack to the roof of multi-story apartment, under the cover-story that you're taking photos of the view to share with your friends and family, because if SHTF because people, who are like you or are you, might find these stashes and throw them down at riot police and their vehicle windshields. This would be very bad and very illegal.