Think you confuse matters: A currency should have "a predictable purchasing power", not a store of value. Latter should rather grow (which requires a deflationary nature/limited supply) and offer stability in times when stocks and/or currencies nosedive. Gold is not that bad for this use case and BTC is even better.
But instead of so much meta talk I would be happy if you let me know which asset is a better store of value than BTC and why (for all kind of countries, also those with weak economies/currencies/infrastructures).