Most everybody's gold is held in a vault. You rarely get to touch it. But you don't have to. You know you can't take a bar and go buy a car. But you don't care.
I expect if I walked into a car dealership able to pay for a car in gold they would gladly accept it if it meant a sale.
Try it. Unless it's obviously 10x the car's value or something... they'll tell you to take it to a bank first.
Even if it was 10x the car's value. How would a car dealership know it was real 24k gold?
If it was recognized gold bullion coins and I walked in there and had a plausible reason for why I wanted to do the transaction that way, why should they say no and lose a sale? They would do a thousand jumping jacks on the showroom floor upon request, or bring in a masseuse to rub you down while you signed the papers, if you seriously convinced them that's what it took for you to buy the car from them, as silly as it sounds.
How would the car dealership know it was 24K gold? How do they know that when they hand me the keys for a test drive, I'm not going to just drive off and never return? I'm sure they'd make sure they had some sort of recourse before accepting such a deal (after rolling their eyes etc.)
You're talking about minted gold coins there. Not gold bullion. Yes, a minted gold coin is legal tender. But that is not what I was referring to. I meant gold in terms of bullion/bars/what most of it is held in.