As someone whos home is directly underneath two of them: their flowers somehow get through 2mm gutter guard mesh, and rot (which is annoying as heck and slippery if you're not paying attention).
They're pretty, for sure, but they're not without their detractors
Another tree used as a street tree here is white cedar (native) and it would have the same problem with rotting flowers, plus far more annoying fruit/berries that cause slips and try to start rogue trees all over the place.
Incidentally, what are considered ideal street trees? I know plane trees are out of favour (lots of leaf litter, annoying flower ball thingies). Crepe myrtles aren't tall enough for roadside plantings.
Yeah there's also the Leopard Tree which has the same problems around leaves too (we have one of those above our house as well!). I honestly don't know what would be better, I don't know enough about trees!