[vardump]

Extra swappable batteries take way less space than external battery charging packs. Charging cables are also a pain on the move.

Useful when out of charging range for an extended period, like when hiking or cycling.

[XorNot]

Charging cables, adapters, dongles - these are all things most devices cannot go without, and which take up tons of room in luggage or bags as well.

I've been less then thrilled with Apple punting every design problem into a dongle.