There's also the issue that the battery is fairly valuable and can be damaged/depleted. If I normally charge at home, take care of my car, and have a good condition battery, how happy am I going to be if I take my car on vacation, do a battery swap at some station far from home, and only when I return do I realize that the new battery has been heavily used, and only has 80% of the capacity of the one I swapped out?