what you saying makes no sense.
why would coins have to be destroyed? what good would that do other than destroy the ability to keep buying gold?
you buy gold, the coins are resold on the exchange and used to buy even more gold...its really simple to understand
I think he's under the impression that Gold is being bought directly for gold. Its not. Even if it was then still no need to destroy the coin. That would be like destroying fiat currency after you buy gold. Theres no need the receiver of fiat to burn after selling of said gold.
That's not how financial transactions work.