The Tarot, also known as the Devil's Picturebook, is a picture book of the macrocosm. Holding a tarot deck is like holding the world in the palm of your hands. If you use it for magic, you are a god. The true magician will know how to use the deck instinctually, as the instructions are self-contained. Ask, for you shall receive.
I understand the Lucifer story as a very Roman battle. Being cast out of heaven and demonized makes perfect sense in the context of "thy will shall be done on earth as it is in heaven." He was demoted to elder god (devil) when the new god(s) took over the state of Rome, when they ushered in the era of Christianity. Hence the story of the war in heaven. Don't forget that Lucifer was never a Hebrew god. A millennia after the "war in heaven" the first tarot decks were published in Italy, and so the devil was loosed after 1000 years. Thus Christianity gave birth to not only to the devil, but also to the tarot cards.