I like commodities as a hedge, but I don't use them as a primary investment vehicle. Any commodity (beans, bullets) can be used as a currency in trade, but both precious metals and Bitcoin make for nice fungible and divisible options for units of account. Both also have downsides. Physical security and storage for precious metals is tough, especially in a scenario that mimicked the post-Depression ban on personal ownership. Bitcoin cannot be seized or detected at any physical checkpoint, and so does make for a highly transportable store of value in such circumstances. Real-time trading of Bitcoin can become a problem if a country suffers a massive infrastructure failure - but to lose it completely, every global communication network would have to be blocked or destroyed and every one of the millions of copies of the blockchain eradicated from the face of the planet. In such a scenario, I think store of value might be a distant concern for most....
The main "problem" with Bitcoin is the average Joe does not understand computer security, encryption, or free and open source software, even at basic levels. This makes it easy to steal Bitcoin from these folks, and to block them from trading effectively if network filters are applied like the Great Firewall of China - most users just wouldn't know the first thing to do. Most people can figure out how to trade a chunk of gold for a bag of rice on the other hand, if they can hold onto the gold.
If underground or black market trading are your thing, nothing compares to the paper USD in volume or availability the world over. Just have to watch out for that pesky "civil asset forfeiture" problem, currently the #1 theft racket by dollar value in the US by huge margins.