America will get around to it, but America never does anything without taking a long, long, long time to investigate it first. What are the pros... what are the cons... what are the aftereffects of the pros... what are the aftereffects of the cons... what are the pros and cons of those aftereffects and can they be delayed/hastened to make them beneficial... It's why policy meetings in the U.S. are so bloated and stove-piped.
That two-edged sword shields her from a lot of rash decisions but it has also kept her from jumping in on the ground floor of a lot of innovations. But anyway, all of that was to say America will get around to embracing something like cryptocurrencies eventually, but not when there are so many question marks surrounding the entire market right now.
As for China, they've been playing "go away, no wait a minute" with the cryptocurrency world for the past few years, and it's generally believed that they're working on a digital currency of their own. Now the CCP never likes anything that's decentralized but I think they've found a way to get around that.
The coin itself can be decentralized without them losing their deathgrip on domestic power, as long as they hold ironclad control over the only apps whereby it can be exchanged.
From living in Beijing for the last five years, I believe that the meteoric rise of WeChat Wallet and Alipay has been a test run for this, and the introduction of a Cryptoyuan (which will not be tradeable through any means other than those two, which the CCP can lock you out of for disloyalty) will be their next attempt to get the global "ooooh, aaaah" factor working back in their favor. There's a nagging worry in my mind (one I've dismissed as nonsense but which won't go away) that it has darker implications as well. At the risk of being a spammer, I actually just mentioned that in an entry this past week.