SmartCar as a city car
This car was used in the Car2Go one way car sharing program that Mercedes launched in the North America and Europe.
It was a great program but in reality, would only work in a few places ("Car2Go dying: further effects from the rise of ride hailing and damage to the sustainable mobility platform/mobility as a service paradigm"), so it could never scale the way a large corporation like Mercedes would want, and they shut it down, although it still operates in some cities in Europe.
This photo of the car in a local supermarket parking lot in South Salt Lake City shows one of the key advantages of the SmartCar as a city car--it's small and easy to park. It got great gas mileage and the electric versions were a dream.
The problem with the market for cars in the US is that it isn't particularly differentiated, with different vehicles for different purposes.
So sure a small car makes sense "for the city." On the other hand, people tend to buy "one car" to meet a maximal number of their likely and intended uses. So people aren't going to buy a small car for the city uses when they want a bigger vehicle to accomplish longer trips, carrying more people, etc.
Plus, car dealers aren't motivated to sell small cars because they don't make much money off them (not unlike how bicycle shops aren't motivated to sell low cost city bikes compared to expensive road bikes).
But then that's why the one way car sharing application was so great for cities like DC and Seattle.