My argument is that the same organization is the one specifying whether a particular piece of paper or commodity can or cannot be used, and under what conditions. As we've seen in the United States, currency is only legal tender because the US government says that it is - there is nothing intrinsic about either fiat, representative, or commodity-based currency as a legitimate means of exchange. All of these classifications can be changed at any time (Emergency Banking Act of 1933).

Why, again, should I care about whether or not my dollar can be converted into silver if the government can, overnight, revoke redemption and outright ban ownership of the underlying commodity?