This is an opinion and not a rational explanation of why the Federal Reserve lists this gold as an asset. They are not ones to fool with the irrelevant. Your point about the price of gold in 1965 is invalid as the price of gold vs the dollar did not float then. However now that you brought it up, your irrelevant relic was being sent to Europe by the ton to cover the dollars that were being printed then. Nixon closed this gold window in 1971 before the USA ran out. (testimate enough to its importance to the world's financial market) It was the first bankruptcy of the US dollar.
Sure, of course one can do that. Except that nobody uses gold or silver when buying or selling. Your opinion. Gold, silver, etc. may well be useful to have, and I think it makes a lot of sense to invest part of your money in precious metals. But that is about it. Christian