A battery can weigh up to half a ton. Because of the weight, you want to keep it at a low position in the car. That is not easy to swap. By contrast consider that you charge your car. For a daily commute, the most practical is to charge it on your driveway or at the office. In my case that means I only have to consider public charging on vacations and longer weekend trips. Now this means my net travel speed is lower then. But I can adjust to that.