It has the potential to extract information such as codewords from your victims to properly disguise as them, which is something that is rarely seen in changeling.
Of course the voices would have to play along, so the cost is zero. Right now the victim has to play along because I don't want to make being caught by a changeling even more shitty by forcing the victim to stick around and talk to the ling. 
For people that enjoy this kind of thing though this will at least give an opportunity to somehow stay relevant to the game even if your corpse is not going to be found.