In a pinch, you can use one to light a portrait. Come on.
The same link talks about a similar lighting setup in Collateral – a film involving a lot of driving around Los Angeles. Rather than spend a fortune setting up external lights in every location, they decided to just use the existing streetlights etc.. The problem is, streetlights / building lights aren’t nearly as powerful as the usual film lighting equipment, so they had to use extremely sensitive film. This left the interiors of the cars almost black, however, and there’s not a lot of room in a car for fancy lighting setups. So they stuck bright, flat-panel screens to the roof / other hidden parts of the car. Clever.
At some point in the last year I turned into a total lighting geek. I keep having to remind myself mid-conversation that not everyone finds it as interesting as me.