The only legal reason to invest in crypto currencies is if you believe that the local currency and alternative fiat currencies will significantly lose value. That won't be a good situation for the average American who starts seeing rapid inflation in the goods and services that they use. People fleeing the US dollar to other stores of value would only make the situation worse (just as people tried to escape to gold during the 1930s). So at that point, it becomes a political issue. Both political parties do not want to see the US dollar lose reserve currency status. If anything challenges it, they will unite to block the challenge and will have the support of the majority of Americans who will not hold any cryptocurrencies. Online piracy is a bit different. In that case, the product stolen is the end product and the government loses out on some tax revenue. Also, a lot of people who downloaded stuff on Napster would not have purchased the CD had Napster not existed. So it's unclear what total effect piracy had. But if the US came along and said you can hold Bitcoin, but cannot exchange it for dollars, stocks, bonds,PMs, etc...the value of that bitcoin becomes worthless to the holder. I think India did something like this a year or two ago...something about banning physical cash I think... If China really wanted to ban it, they could. I suspect they are just waiting for the right moment. I would not put it past them to establish a big short position before doing so.