> I'm personally of the mind that, as long as I trade with certificates that bear Caesar's face (or trade with proxies for such certificates, like a MasterCard), he gets to make the rules in exchange for my being able to lean on his legal system to protect my interests, so I find that the equitable access angle is nice.

It is a minor point I suppose, but this is the other way round. Because Caesar makes the rules you trade certificates that bear his face. It takes vigour and energy on the part of law enforcement to stop people from moving to private currencies.

> that does depend on what one's definition of a free market is

Sigh. No need to make up one's own definition. Googling "free market":

"A free market is an economic system where prices, wages, and the flow of goods are determined by supply and demand. There is no government control or central planning telling people what to buy, sell, or make. Instead, private choices and voluntary trades drive the economy."