what would you do if your area lost power for six months
If the power is out for long enough, I think you won't be able to pay with cash, too. Stores need power for all kinds of things like registers, lighting and refrigerators. I imagine they would close pretty early if not immediately.
Additionally, long-term power outages are emergency situations if you live in a region that depends a lot on power. There will be looting. You won't think about your bitcoin in such a situation1. You will care about food, shelter and being safe from your biggest threat: other humans in survival mode.

Footnotes

  1. except that you know they are more safe than any other bearer asset
Depends on the reason for lost power for six months - if it's so serious, going somewhere else might be better?