Zephyros
Perhaps because everything has proper measure and proportion. If I have a stone, it is because all the material in it is exactly right so that it is a stone and not a feather. If Tarot is to portray any meaningful picture of creation at all, and not be simply a random collection of pictures, the it follows that it must have the same laws of proportion as anything else. While one doesn't have to divine according to one certain order's spiritual view of creation, heaven knows Marseilles decks don't follow the same tradition, I think it helps to at least admit the pictures do have structure and purpose.