In an unstable or even collapsed society things are different. While true that historically gold could be used to buy things it might be at a very depressed buying power or it can be used when dealing with a stable outside society. A hedge for a unstable society is something that actually has "need", for example, antibiotics. Even then, once violence is a standard part of life and interactions the usual calculus of interactions changes.

History provides examples for societies that kind of collapse but sort of kept going on money surrogates that could get daily necessities at a high price; history also has examples for the violent kind of collapse/instability and there I would not count on bitcoin or gold to help absent access to violence.