When was the last time you truly used, focused on, for any significant length of time, your imagination; your active, conscious, willful, artistic creativity, to get back in touch with that ability to appreciate the wonder that you yourself can create and bring forth, all from within yourself? Were you ever able to do that? Did you ever do that? Can you still do it? Do you do it when you game, as player or GM? Will you do it? Could this be missing from a lot of the newer, younger RPG'ers of today?
Tarot Cards are used by Magic folks to predict the future (cartomancy). Since the present becomes the future through the interplay of elementally alligned forces, the tumble of cards can give clues to the way the pattern of elements will be in the future.
This means a wizard will have a deck of cards with them. Since cards were used to train wizards in legerdemain, Since they have cards with them, they frequently know how to use them. Guild magic users often have a knack for fancy shuffles, palming cards, and a variety of card tricks and games.