Singing to a butterfly gives you an indeterminate amount of experience points but it also costs a great deal of energy--seemingly more energy the further into the game you go. So is it ever 'worth' the energy expenditure of singing to a butterfly in order to gain experience?
It seems like it's never going to be more valuable to sing to a butterfly than just to do the regular things (like making recipes, etc.) to gain experience more slowly but with predictable energy expenditure than to gamble on butterfly singing, but I am afraid there is something in the experience I am missing since I have only done it a handful of times in 25 levels.