I have a butane soldering iron, and its good to have when electricity isn't handy and you have just one or two connections to make like in a car, up a ladder etc. The flame is fully contained though, one of those screen things so it only heats the tip.
This pencil torch would set the car on fire under the dash.

Don't ask me how I know this.
Must be useful for something, but might depend on exactly what the flame is like. Big cigarette lighter or small torch. Even if the flame is small why wouldn't it be enough to heat up a bolt?
BTW I do have a typical quart sized propane torch, but its kinda big.
Wow, I sure hope I don't already have one of these someplace.