Playing Cards Are Literally Crunchy
That Real Life Thing
But I'm serious. Until a minute ago I had no idea cards were crunchy in both senses of the word. Chomping on a Jack of Clubs was an entertaining if unusual experience. The pleasures of it are liken to dipping your hands in a bag of beans or cracking open creme brulee.
So I'd recommend you try it, but to hold these thigns in consideration:
1. Use a not-needed or not-from-a-commonly-used-deck card.
2. Do not taste it. It tastes horrible. Very bitter and plasticy and probably what dryboard markers would taste like.
3. Plan a completely sensible explanation in case someone asks.