Big money is getting behind mobile payments, and for good reason. Forrester Research estimates that revenue from mobile transactions will grow 48% annually from now through 2017.

Growth like that attracts disruptors. For example, WePay has introduced an iOS app for helping small businesses process invoices from anywhere using a credit card. There's also Plastiq, which, according to TechCrunch, just raised a $6 million round of funding for helping customers use credit cards to pay for services that historically have only taken cash.

Do either of these ideas threaten eBay (NASDAQ:EBAY), which processed $14 billion in mobile payments last year -- a 250% increase -- through its PayPal unit? Tim Beyers of Motley Fool Rule Breakers and Motley Fool Supernova cautions against writing off the incumbent, and also offers what he considers to be a better play on the overall opportunity. Find all the details in the video below, and then leave a comment to let us know what you think.