>It is the only thing the government accepts for tax payments. Given that you can be arrested for not paying your taxes it is "backed" by the barrel of a gun, a threat to your very being. In one sense this is the only real thing there is.

That's more than enough reason why we should try something else. It doesn't inspire a lot of confidence. By that reasoning, the USD has the same sort of backing as the Venezuelan Bolivar. So what's to stop the prior from becoming like the latter?