I dislike gold as an investment vehicle, but it is a sensible investment during a localized civil war that does not impact the global economy.
During a civil war, the local economy will be destabilized. This means that local production will drop off, and most things you want you will have to import (this includes the service of fleeing the country). In addition, your local currency will have become destabilized (possibly permanently), so outsiders won't find it desirable. Gold has a market outside your country, so outsiders would be willing to accept it as currency.
Basically, what you want is a currency with a global value, because it won't be affected by local conditions. Gold satisfies this criterion, as does USD in many cases.
I think most of the debate upthread can be summarized thusly: This criterion depends on a separation between local economic conditions, and global ones. In the US there is not such a distinction. If we suffer an economic collapse (whatever the cause), we're taking the world with us. As such, there is no currency with the properties that people are looking for.