While there is some similarity with trading card game packs, part of the predatory design of these online games is that you aren't permitted to trade what you'v

While there is some similarity with trading card game packs, part of the predatory design of these online games is that you aren't permitted to trade what you've bought to other players at all. This prevents the player from trading away unwanted or duplicate rare items for ones that are wanted in order to pressure the player to continue spending.