Bitcoin is great for the underworld; drug money, ransom ware money, anything illegal requiring a monetary transfer that is untraceable. I don't buy this excuse it isn't manipulated or a fiat. If the US decided to restrict transaction because all illegal activity transfer their dealing to this medium the govt policy will destroy value with the strobe of a pen. People seemed to have forgotten a few years back when it crashed. Now when I hear commentaries of 'this time it's different' and the index is in an exponential rally I think this has a greater chance of crashing than US equity indices.