The problem with 1 oz rounds is that they are too big to trade with. Even at $1000 an oz. How often do you spend a grand at one time?
1. I spend one grand at a time on rent, or paying off a bill with a major creditor.
2. For smaller purchases, one can prepay with a merchant for future purchases
3. One can run up a tab and pay it off when it reached $1000.
4. (This is a radical one) The merchant can make CHANGE?
Why do you assume that those who have 1 oz. gold coins don’t also have silver for smaller purchases?
Will your merchant give you change in smaller gold or will it be in worthless collapsed dollars?