I don't think WiFi is a good way for a city to encourage broadband. You note many of the problems, but I also just view it as uneconomical in the long term.
However, I think there is value in WiFi in certain circumstances. The value of WiFi for a city that has substantial fiber assets is to provide coverage for muni functions and perhaps those who know what they will be getting. Building inspectors, social workers, many city employees can be more productive in the field with wireless broadband access but they need greater capacity than the cell networks currently offer and they can save substantial money when they can put nodes anywhere due to abundant backhaul afforded by the fiber network.
I agree that indoor access should be handled by the building owner or occupant. WiFi doesn't penetrate much and offers poor speeds anyway when multiple users are on it.
Christopher is being an activist for St. Paul, Minnesota. I hope he can get further in getting St. Paul to think about deploying broadband over fiber than we have gotten with San Francisco.