You speculate every day you carry dollars, too.
You're holding on to them in good faith that the government won't screw up horribly and devalue them somehow. And unfortunately, that is the case. It is just a matter of 'when' the massive debts the U.S. is carrying crash upon our heads. There is no such thing as perfectly 'safe', but you better bet I'd rather hold bitcoins in the long run than fancy green toilet paper.
truth