Board Thread:Game Discussion/@comment-94.204.11.232-20161231120321/@comment-107.130.170.163-20161231191451

They want you to buy them to finish them off. Even if you refuse to do it, it's what they want. Other than that, there's really no purpose to the stickers other than the creators trying to make you want to feel the urge to complete the collection for your own pride and sense of accomplishment. That's it.