Apple CEO Tim Cook says his company is intrigued by the mobile payments space, and that its interest there is one of the reasons for creating Touch ID. "The mobile payments area in general is one that we've been intrigued with," Cook said on a conference call discussing Apple's Q1 2014 earnings. "It was one of the thoughts behind Touch ID."

"It's clear that there's a lot of opportunity there."

Cook said that Apple has seen great response from customers to buying music, movies, and books using the iPhone's Touch ID fingerprint sensor, and that "It's clear that there's a lot of opportunity there." Just last week, it was reported that Apple has begun building up a mobile payments division, though further details are slim.

While Cook declined to go into specifics, he was forthcoming in suggesting that mobile payments was an area that investors wouldn't be foolish to expect that Apple move in on. "You can tell by looking at the demographics of our customers and the amount of commerce that goes through iOS devices versus the competition that it's a big opportunity on the platform," he said.

Touch ID already includes a basic mobile payments feature: the ability to pay for products on the iTunes and App Store without entering an account password. While that's a limited use for now, Apple already has millions of customers' credit cards on file with iTunes, giving it plenty of potential to expand where Touch ID is used for payment.

Cook also said that Apple doesn't intend to limit Touch ID's use to just mobile payments. It's unclear exactly what else Apple may have in store for Touch ID — especially since its primary use right now is for unlocking the iPhone 5S — but it seems that there are big things to come for the tiny sensor.