Australia seems like kind of a mess on this front. There is a bifurcation going on where some of the more affluent nations are moving in a cashless direction, but my take is that this is only a segment of the planet (Australia, the most affluent Western European nations, upper crust demographics in U.S.). With 18 billion individual hundred dollar bill notes being hoarded and circulated far and wide around the world, I see dollar cash as quite unlikely to fade out for a good long while. Try traveling just about anywhere outside Western Europe and US with dollar cash in your pocket and listen to the sucking sound.