Gold is always in demand as a luxury item for jewelry and decoration. The fact that it's primarily wanted for luxury and not for practical purposes is actually in its favour - peoples wants are unlimited, whereas their needs are finite. And a metal that's needed for some practical purpose one day, might become obsolete the next.
Aside from that it's ideal for currency because it's fungible (all gold the same, so exchange is easy), portable (small amount is worth a lot, also easy to melt down into smaller lumps), durable (doesn't rust or rot).
It's a virtuous circle whereby its intrinsic physical properties and luxury status make it a good choice for money/currency, which then gives it a new dimension of value as that idea spreads.
Aside from that it's ideal for currency because it's fungible (all gold the same, so exchange is easy), portable (small amount is worth a lot, also easy to melt down into smaller lumps), durable (doesn't rust or rot).
It's a virtuous circle whereby its intrinsic physical properties and luxury status make it a good choice for money/currency, which then gives it a new dimension of value as that idea spreads.