The SmartCard and WalMart crypto currency

When we all have our smart cards, WalMart can run its own crypto currency.  We can buy WalMartCoins at the store, or sometimes banks sell them; placed right in the Smart Card. Useable only in WalMart Stores, but great discounts.  Home Depot return credits could be placed right back into your SmartCard using HomeDepot Coins. We get an active on line market, trading WalMart for HomeDepot.  Sounds like fun, actually. Hey Fidelity, where is my UniCard? Seriously, why is this not big business, and why isn't WalMart and Home Depot pushing the idea, a universal smart card protocol, handles a variety of digital transactions in a variety of different digital currencies. No one would leave home without one!