The "Ghost" cards can't be traded at all, they are merely intended for cards that starters can play with. The 10$ purchase of the spellbook is the cost to start earning DEC by wallet. It seems that bots can use the Ghosted cards and win the daily chest at minimum. Newly released reward cards are still trading at a dollar so bots can breakeven in time. The money is with the reward chests not the issue with Ghosted cards.