A wide ranging article covering mobile payments, mobile money and cryptocurrencies by BNY Mellon (who have an amazing museum with some antique currency dies and plates) and Wired Magazine.
The point is, currency for hundreds of years has been an evolving form of technology, with the faster, better, cheaper underpinnings found in all great technologies. But arguably, not since the arrival of the greenback has currency been poised for a more dramatic leap forward. Digital currency is finally taking hold. Driven by two massive technological waves—the Internet and the mobile phone—digital currency is bringing banking to the unbanked; it’s making new forms of transactions financially feasible; and it's allowing currency to do things it could never do when trapped in a physical form.