The Wallet card will let you pay for items at any retailer, even those that don't have the little NFC kiosks Wallet has thus far relied upon. The charge should be relayed to your Wallet account just like you had used an NFC phone. It's unclear if that's just the Wallet balance, or if cards are included too. This fits nicely with Google's strategy of uncoupling the NFC payments in KitKat from the hardware secure element. Google is really making Wallet easier to use on multiple fronts.