Should people be encouraged to hang around near an intersection? Surely the pollution is off the charts. How about just banning cars 1 day a week? Then 2, then 3...
Banning cars is a political disaster without serious alternatives. The paint is mostly to improve public safety when crossing the road, and if you have a lot of leftover space all of a sudden, it's better to convince people to use it rather than turn it into a desolate space orphaned and abused by the community that becomes dirty and crime-infested.