One big difference that Amazon has with other companies that try and lock people in with virtual currencies - Amazon already has more credit cards on file from

One big difference that Amazon has with other companies that try and lock people in with virtual currencies - Amazon already has more credit cards on file from customers that trust the service and willingly shop from there than just about any other company in the world. So I'm sure there's a reason for this, but just because of the sheer number of credit cards they already have on file I'm having a hard time seeing a real rational for this move. Are they really trying to effectively trick gamers from buying useless game add-ons by divorcing that from its actual monetary cost? Are they betting that heavy hitters on Farmville type games will make this worth their while? That's the only reason I can kind of come up with. If this is the real motive, I'm a bit disappointed because I expect more from Amazon.