In a landmark moment, the Cash app from Square has now passed PayPal to become the #1 free app in the finance category in the Google Play store based on downloads.

Cash in many ways resembles competitors PayPal and Venmo (currently ranked #3) in that it facilitates simple money transfers between individuals or to product vendors. One crucial difference, though, is that since August, Cash—a general-purpose payment app that mostly targets dollar transactions—has integrated bitcoin, too, making it easy to buy.

Once Cash users have linked the app to a debit account, they can buy and sell bitcoin from their U.S. dollar balance with just a few swipes and clicks. There are no fixed fees, but Cash’s support page for bitcoin notes:

“Your exchange rate for buying and selling Bitcoin through the Cash App is calculated using the current market rate across the most popular U.S. exchanges, plus a spread determined by the size of your transaction and market volatility.”

Like any currency exchange service, Cash presumably extracts a profit from the differential between buy and sell rates offered, although it doesn’t offer exact figures. It won’t offer the kind of precision that crypto traders look for—but that’s not the point.

As a rule, casual users don’t want to post buy or sell offers on an exchange and wait for a taker to fulfill them. PayPal’s enormous success shows that most of us are fine with losing a few pennies on the dollar to send money through a service that is simple, quick, and user friendly, and Cash’s user experience is just that.

Adding cryptocurrency support to general-purpose applications is a huge step toward mainstream adoption, and something that is becoming more widespread. Recent reports suggest that Samsung will include a cryptocurrency wallet with the Galaxy S10: a device aimed squarely at the mass market, and which is all but guaranteed to sell tens of millions of units.

Jack Dorsey, CEO of parent company Square (and also Twitter CEO), has previously declared his belief that bitcoin will overtake the dollar in importance within a decade. Though the short-term market outlook for bitcoin has been less than rosy, apps like Cash are making this long-view prediction seem more realistic by the day.