I bet there could be creative situations where it could work. Imagine a rig that joins to an electric overhead line (like a light rail). The rig could move at the speed limit around the ring-loop of a city's interstate. Cars can pull alongside it to charge. If it had enough arms, and was narrow enough you could charge quite a few cars. If its then charging from the grid it needn't actually be propelling a battery at all.

Or in a situation where moving the battery already happens. Maybe where a whole fleet of trucks have purchased into a booster pack scheme. The booster packs fall on and off at various cities along a long route. Kind of like jettisoning a space shuttle's boosters. On either side of the city you have 50 packs charging. Radio that you need more juice and as you hit the city limits a booster latches on, you trail it through the city charging your main pack back up, and drop it off on the other side of the city where it charges and waits for someone going the other way. The truck never stops, it just keeps going and gets 'boosted' by a self-driving battery trailer every time it's within 100 miles of a city.

Or allow you charge-up without really doing anything. Stay inside your car and read at the supercharger station!

Or, cars become a shared resource and you just call up basically a driverless Uber when you need it. That's the future I want to see in e.g. areas where mass-transit is blocked politically (e.g. BART from SF to SJ) or where the population density is such where it doesn't make sense.

Looks like Elon plans on competing with Uber.

http://qz.com/473803/tesla-ceo-elon-musk-on-potential-uber-p...

Imagine your robo-tentacle in drab safety black-and-yellow, have a hundred of them waving in the dark waiting for their JohnnyCabs to come in for a charge between fares...

The tyranny of the self driving self driving car refueling bot.

In stunt mode you could just gang several Model S batteries together (which would fit in the back of a pickup). I guess the idea isn't very practical though.