A swappable battery would require hardware in the phone to receive it. That would take up useful space inside the phone that could be used for other stuff.Someday, in the faaaar distant future, one of the million or so amazing magical geniuses in management at our finest tech companies will dream up the brilliant idea of a standard removable, swappable, spare battery. A full recharge in an instant. Minds will boggle. The world will not have been able to see it coming. The earth will explode in excitement. Everyone will live on the moon. Etc.