I think they can be insightful and full of things to meditate on even if they aren't real.
I believe cartomancy is real.
Worth noting, you can use standard playing cards 52 or 32-card piquet stripped decks for divination
There are different kinds of tarot such as estoric decks which have 78 cards divided into two sections: the Major Arcana with 22 cards and the Minor Arcana with 56 cards.
Then theres Lenormand decks which have 36 cards, Teuila decks which have 45 cards, and various Oracle decks that can have any number of cards.