You're correct, but like Jeremy said, they have mobile apps in both the Apple [1] and Google [2] Store. Funny enough, they both have over 2000 ratings at 1 star.

[1] - https://itunes.apple.com/us/app/currentc/id912922036?mt=8

[2] - https://play.google.com/store/apps/details?id=com.currentc

Yes, but they need to have their payment apps on the devices to make those physical transactions.