A few other stupid card tricks you can use in your tabletop RPGs:
Playing cards can be used to implement large random lookup tables where duplicates results need to be avoided without resorting to forced rerolls. (Tip: remove the aces, jokers and court cards from a standard poker deck, leaving only the 2–10s of each suit, and you've got a set of cards which can be used to double-index a full d66 table to allow it to work with either cards or dice. Also, you just set aside 18 cards, so you can use those to double-index a separate half-d66 table if you need both.)
Even when you're using playing cards as ersatz dice (i.e., just drawing the top card from the deck and treating that as your roll), the drawn card automatically furnishes a persistent token representing the result of that "roll"; this token can then be fed into a resource economy, retained as an historical record of the outcome, or both. (For example, Rose Bailey's Beautiful Anomalies, in which "rolled" cards are played face-up on the table into a linear queue from which the GM draws, allowing players' actions in the present to control the GM's dice rolls in the future.)
In physical play spaces, the fact that cards have face-up and face-down states allows randomised outcomes to be made known to some but not all players much more easily than with dice. The face of a drawn card can be selectively shown only to certain participants, while a played card can be placed on the table face-down to offer assurances that the unrevealed outcome hasn't been tampered with. (This can be done with the outcomes of dice rolls via note-passing, of course, but using cards in this way removes the need to trust that the note accurately reports the unrevealed roll, which can facilitate some types of adversarial play.)
Building on the previous point, cards have extra axes of statefulness. A die typically offers only the rolled number and its position on the table as stateful information, but a card can be face-up or face-down, placed in an upright or rotated position, etc. In face-to-face play, cards are also much easier to move from zone to zone on the table when position-as-state is required, making them better suited to applications where randomisers double as resource tokens or playing pieces.
Deckbuilding. It's a lot more feasible to give each player a personalised mini-deck of cards to draw from than it is to give each player a set of dice with customised faces; if you're determined to bring deckbuilding mechanics to the tabletop, basing it on actual playing cards is going to be a much easier sell for potential players than asking them to screw around with papercraft tokens or blank dice and markers. (Or, heaven forefend, asking them to actually buy custom dice which can only be used with your game!)
Finally, standard playing cards get you a lot of cards for not that much money (you can usually buy three to five full 54-card decks for the same cost as a single set of standard polyherdrals), which is a strong selling point in contexts where you need (or want) to be throwing around lots and lots of individual randomisers and would prefer not to go the "great thundering handfuls of dice" route.
