In tbe event of a massive catastrophe, gold is worth MORE than money. Think of it this way, name a civlization in history. Would you rather have $100 of their currency now, or $100 worth of gold from that era now?
$100 worth of gold bought at $850/ounce buys 0.117 ounces of gold. Today that gold (at $1181/ounce) is worth $138.90.
Your cash is worth $100.
The gold bull run of the 70s peaked at $850. So, even if you bought an ounce of gold at its peak, you'd be getting about $1300 for it today.
Cash, on the other hand, would have inflated away quite a lot, so your 100 bucks would buy you about 40 1980-dollars' worth of goods and services today.
But this still highlights the problem with this scenario: currencies lose value over time. They do this by design to encourage people not to hoard currency, but instead to exchange it for goods and services, which encourages people to produce goods and services. Because of this, any non-perishable commodity is going to gain value over time relative to a fiat currency. There is nothing special about gold in this regard.