Sorry, I guess I conflated it with your initial statement of "What currency is not being used in the drug market?".
The first difference to come to mind is that if you forget the password to your gold, the gold still exists. If you forget the password to your wallet, your bitcoin is pretty much unsalvageable. And assets that are so easy to destroy aren't particularly stable. And yes, most wallets have all sorts of backup capabilities and safety features, but in the end it's used by humans and humans are stupid [citation needed].
The first difference to come to mind is that if you forget the password to your gold, the gold still exists. If you forget the password to your wallet, your bitcoin is pretty much unsalvageable. And assets that are so easy to destroy aren't particularly stable. And yes, most wallets have all sorts of backup capabilities and safety features, but in the end it's used by humans and humans are stupid [citation needed].