Unless I'm missing something, there really is little point for duplicate cards, besides selling them for extra points. Since these duplicate cards take up space in the inventory, I'm thinking it would save some player time (that could be preferably spent on actually playing the game), if these items were eliminated completely.

Instead of going into the item inventory, it would be slightly more convenient if the cards went straight into the card list. If a duplicate card is earned, the player could be rewarded with bonus points (equal to the selling price).

Also, a more prominent notification, than the current inconspicuous line in the chat log, when the card was added would be nice too (like the atma notification with the sound effect)

Just a minor something I've noticed. Unless of course they have future uses for these duplicate cards (maybe implementing the option to trade them, for example).

Perhaps a "please look forward to it" is in order?