With the new system, slated to be rolled out this fall, Visa is making on a bet on NFC technology, which many industry observers believe will become the standard format for mobile payments.

Mobile wallets face several hurdles in their transition to the mainstream, including a lack of standardized technology, fears about data security, and established physical payment systems.

The truly impromptu payment may be the last great frontier for cash, until the mobile payments infrastructure supports widely accepted secure payments standards.