Beanie Babies were a store of value for a short time, but their values eventually dropped to nothing because they had very little utility.
If Bitcoin were no longer used as a payment system, then it will also have been just another fad, and its value will drop to nothing. Basically, what good is a bitcoin if you can't spend it?
Gold and Bitcoins are actually more similar than people realize. People say, well, I can hold and touch gold. But in reality gold is fairly useless. You can build with it (well, Mayans did, haha), you can't eat it, it can't keep you warm, etc. Gold has a value of X an oz right now because that is what someone is willing to pay for it, simple as that. Bitcoin has a value of X right now because that is what someone is willing to pay for it.
Other metals have a lot more use than gold but gold has become the "standard" over time, its rarity contributing partly to that.
Bitcoin has become valuable because it was first to the market and has a fairly limited supply of coins in the world.
If Bitcoin can't buy anything, it's basically worthless. Wool will always have a value, albeit small, because you can do something with it. Bitcoin and gold you cannot.
+1
In reality if the #*^% hit the fan the way the OP is saying, the only things with any value will be food, water, shelter, bullets and possibly fuel.
No one will care about any currency including fiat, precious metals or crypto's