It works on quite a number of minor characters scattered across the game map, from tieflings to goblins. Typically it gives you an alternative to a set of skill checks.
Try it when talking with the tiefling holding Sazza at crossbow point, or the one who's failing badly at skewering a practice dummy. In the goblin camp you can use it to get past the guard into the temple interior or finagle the dead dwarf's belongings from the goblin at the spit.
