My thoughts is that there might be a potential market for the physical side of things alone. Making the scratchier on the outer pack a potentially good idea. In other words; those who don't want the digital assets but still want to collect the physical cards. The fact that the scratch off is scratched would be the indicator that the digital assets has already been claimed. With the system you mention in your OP, such physical items can be traded in two ways regardless of where the purchase code is. (1) the digital assets are handed over with the resale of physical assets (2) The purchaser of the resold pack/card gets the physical card but not the digital assets/benefits that the original purchaser already claimed.