One has real value in the market and is minted for that purpose,...

One has real value in the market and is minted for that purpose, the other you mention you can do a runner like flash gordon because it's only good will, in reference to other commodities for instance like say crude oil you can't pay someone with this.

So gold and silver are also a commodity and a form of payment if you wish and no one can stop you using it as such, you can buy a house with it if you want. How many lawns will you cut to purchase a house? if the seller agrees to that scam.

I'm not trying to be smart just saying it as it is...