Except for transactions, plastic cards are kind of “dumb,” said Ben Milne, CEO and co-founder of startup payment network Dwolla, during a mobile payments panel at Business Insider’s Mobile Advertising conference yesterday.

That’s why smartphones — emphasis on the “smart” — as wallets are poised to offer more value to consumers than plastic cards. It is just a matter of figuring out which features will prompt people to pay in a new way. And it sure won’t be the technical means of payment that will provide consumers with the most value.

Who knows what functionality will drive consumers to shift their payment behaviors. Milne’s money, though, is on it having to do with fostering serendipity for consumers, like pre-ordering services. If a consumer always buys a latte at the same Starbucks, surprise him with having his latte already made, Milne suggested. In other words, reducing friction when customers pick up their stuff “would be pretty badass,” Milne said. Certainly, this notion is one that PayPal has been attacking with its wallet.

From the brick-and-mortar standpoint, merchants will change for new technology that drives down their costs and increase their bottom lines. “It’s that simple,” said Milne.

And though rewards will incentivize usage of digital wallets, that adaptation trick is not specific to the mobile channel. There’s always an element of “what’s in it for me?” – mobile or not, said Milne.

Milne bets on Apple for “crushing” the digital wallet scene. “If Apple does it right and first, it will win,” he said.