Square. Square has invented a smooth, cheap, flexible virtual transaction system. Paypal works only online. Dollars work only offline or online through expensive credit card companies. Square instantly makes offline transactions into online ones, utilizing small-computer technology.Your smartphone talks to Square.
Square and Starbucks have struck a payments deal. As an astute analyst has pointed out, Starbucks can now use the Square system to extend the purchasing power of Stars. Square's technology doesn't see a difference between dollars and Stars, at least not natively. I suppose there will eventually be a regulation. But for now, there's no reason why Starbucks cannot issue Stars at will, and allow people to spend their Stars through Square on anything you can buy in Square. Which is, anything.
Square opens the doors for all loyalty credits to acquire general economic liquidity. There may be a first-mover advantage, in which case, Starbucks wins. Move over, Fed: Here comes coffee cash.