I've never seen any of those lol. And so? What does not dying have to do with anything? xD We can still do immortality as a curse, but why not hearing voices? They dont have to see the ghosts; just hear them.
Overrated? How? The spirits could, like, help them along the way because maybe they died the way the sisters almost did. And they wouldn't be able to see the ghosts completely--and they would only communicate telepathically.