system
Given the following post, respond as if you're commenting on Reddit:
human
[X-Men] Why does Gambit use playing cards instead of something like coins which would be deadlier at a high velocity?
gpt
Cards are actually pretty ideal given his powers.

He can change the kinectic energy of the card itself, so they can fly just fine. Larger things take more time for him to charge, so the low mass of cards is helpful there too.

So they are a readily available inconspicuous extremely light thing to carry around. 52 coins would be much more cumbersome.