"A fortress soon becomes a trap."
If you ever get the chance and take the time to read "The 33 Strategies of War," by Greene you will soon appreciate the value of mobility vs being trapped in a bunker with no way out.
With Bitcoin, you can "take it with you," your mobility is not thwarted — especially if you have your pass phrase memorized. With millions of dollars of physical gold… you're looking at trying to securely transport hundreds of pounds of metal. You won't be able to sneak it through airports. If you're carrying gold and you get stopped by bandits, pirates, soldiers, or border guards along the way, you can kiss your gold (and perhaps your life) good bye. Meanwhile, Bitcoin is not detectable — especially if you have your pass phrase memorized.
If you're preparing for when SHTF and you decide that physical gold is for you, instead of Bitcoin, please remember to check each and every bar in case of counterfeit, gold-coated tungsten. Remember, you need special equipment and know-how to detect it correctly. Oh, and have "fun" hiding in your little bunker. Good luck if/when you decide to emerge…