Many don't know this - but under NYC is the Federal Reserve's gold vault that holds approx 300B in gold bullion. Most of that gold is held as custody for other central banks, and that gold is intrinsically tied to the foreign reserves those nation-states have with each other.
The area itself is partitioned into separate holding areas - each designated for a different client. When trade happens between these member banks, the gold is physically moved to that clients holding area....as described here....
The Fed charges $1.75 to move each bar of gold. Gold bars are moved between the compartments whenever one account holder pays another. Staff wear steel-toe footwear to protect their feet in case they drop one of the gold bars weighing 28 pounds. Every time the compartments are opened or gold is moved, three Fed staff members are required to oversee the transaction. Each compartment is further locked behind a padlock, two combination locks, and the seal of the Fed's auditor. source
So when you see a headline on the news: South Korea Increases Reserves of Mexican Peso as Trade Increases, what is really happening is that some man with a hand-truck are moving a few pallets of gold from an area on the floor named Korea to the area with the sign Mexico....
The implications for Bitcoin should be obvious. As Bitcoin finds its way onto sovereign balance-sheets it will take over this role.
Heavy rocks uneeded.