Another aspect I'd wonder about is the cost for whatever organization is responsible for maintaining lamps in a district, presumably a slower charger is a lower

Another aspect I'd wonder about is the cost for whatever organization is responsible for maintaining lamps in a district, presumably a slower charger is a lower specification and would be cheaper and more likely to be widely fitted or for the project to be approved in the first place, and limits the demands on the local electrical infrastructure. Once the initial install is done in a lamp it would seem that upgrading in future would be a smaller hurdle.