Short answer: To tackle climate change and tackle urban heat islands, we need to increase tree canopy and biodiversity with an emphasis on native plants as much as possible.
Council-planted street trees with resident-planted native understory gardens also suit the multiple purposes for this common land.
Most disputes with verge gardens involve food gardens.
For a more comprehensive answer see Why I Won’t Be Growing An Edible Verge that I wrote in 2017 when I began verge gardening.