I'm playing this module, so please, please keep answers spoiler free!
I just obtained an official Curse of Strahd Tarokka Deck. My character just obtained one tarokka deck as well. My character has Augury prepared and of course wants to use the deck as spell-casting focus for that spell. But are there any other ways for the deck, both as a prop and as in-game item to be useful and add fun, dread and mystery to the game?
I'm not looking for your ideas. I'm looking for ways described in the module, or lore from previous editions and visits to Barovia. Anything published goes.
If there will be story parts when a deck owned by character will make a difference, please liberally use spoiler tags so I, and other readers, can decide if we want to see them. If there are skills that characters can pick up, describe them and only hide specific story surprises associated with them, or with learning them, please. As far as I understand deck is only available after Madam scene, so that's no spoiler.