True. But.... and it's a really big but, with currencies issued by states there's national economies, central banks, millions of people, billions of real assets bought and sold every day, and an enormous amount of political power (in the form of literally millions of people) backing up the assertion that it's worth something, and putting pressure on governments to keep it being worth something. There is no bitcoin state to prevent a run on the bitcoin. Obviously that's a selling point if you want to have untaxed wealth, buy drugs, etc - none of which desires I'm knocking, for the record - but I don't see how it ever becomes a means of exchange, rather than what it currently is which is a means of speculation to gain profits (which people always quote in those 'fake' currencies like pounds and dollars, for some reason). I don't see how bitcoin can ever gain the mass agreement of millions or billions of people that it's legitimate, reliable, and reasonably fair. I don't accept my wage in euros because Angela Merkel tells me it's worth something, I accept it in euros because I can reliably pay my rent and buy what I need with euros. So in the long run I do think cryptocurrencies are a ponzi scheme. But by all means fill your boots in the mean time, and maybe I'm the mug for staying out.