It's left up to the player's interpretation what the butterfly signifies.
I think it's more meaningful to let players interpret it. Interpretation is part of the interactivity. If I told you what I personally think it meant when I was drawing it, or what I think it means now, I have a feeling I'd get an "oh" reaction. Not because I'm telling you specifically; I just think others' interpretations are better because it's theirs. They get to walk away from the game with it.