The whole idea of importable/exportable decks that I proposed had only one thing in mind for me; convenience. People who did not want to buy more deck slots but happened to need for some reason could just export one of their decks and keep it safe someplace else. It was out of the hands of Lightmare at that time. If you needed more deck slots and was willing to spend some time in it, you could either seek out a quest ingame rewarding that deck slot, or buy one for real money.
If it took me 6 hours of uninterrupted play to earn a deck slot, I might consider chucking money at it. I'm not talking lunch money here, I'm talking roll of candy money. Paying for convenience, not for necessity.