How is a gift card that lets me buy virtual costumes not a "a store of value and a medium of exchange?" It's literally a medium that is accepted as payment for

How is a gift card that lets me buy virtual costumes not a "a store of value and a medium of exchange?" It's literally a medium that is accepted as payment for clothing, dance moves, music etc in the store. Kids are doing chores in exchange for vbucks. They can take that gift card and sell it to a friend for USD. On that note, where does it say it needs to be convertible back into USD? It's only "unconvertable" once its redeemed. Plus, you can always sell your account, despite it being against TOS. Obviously the IRS doesnt care one way or another if the value of the vbucks is pegged or inflates, as there would be no capital gains.