Okay, you sell your car for gold coins, good enough so far. Then what do you do with the coins? Do you put them in a box? No, more likely, your going to deposit them in a bank, or exchange them for some piece of paper somewhere down the line. That’s the part I can’t get past.
Just because I don't know how to deal in/with gold doesn't make it any less tangible.
It doesn’t have to be physical gold. 100 years ago when most of the world was on the gold standard, paper money was exchangable for gold. Right the way up until 1914, you could go to the Bank of England, hand in a £1 note and get a 22 carat gold sovereign in return. It was a system that worked for over a century before it was usurped in favour of fiat currency which is based on nothing more than what the bankers and financiers say it is worth.
Would you be happier if he melted them down and sold the gold as new bars without the ISIS stamp?