Let's see if Bitcoin is comparably volatile…
Oh, it's highest point was only 1920% higher than its lowest point. That's definitely the exact same as gold. /s
Also, that ignores that gold has been a store of value for millennia. It's almost synonymous with wealth. In a total financial collapse, if all modern technology dies, you can be sure gold will still have value. 99.9% of people have no idea what Bitcoin is besides funny computer money.
People who believe that it would be "easy" to trade gold for other goods have also clearly never tried - since the entire modern banking system came into existence on the basis of the sheer difficulty of directly trading gold for other goods. No one knows how to value gold, they don't know what it's worth other then a brick is probably a lot. If they could, then the fake jewellery scam wouldn't be as successful as it is[2].
[1] https://en.wikipedia.org/wiki/Price_revolution
[2] https://www.kiro7.com/news/local/just-say-no-walk-away-fake-...
Stores of value are things like stocks, bonds, treasuries, real estate... and yeah commodities like gold and bitcoin. People don't care so much about volatility if they're planning to park their value there for a long time.
https://en.m.wikipedia.org/wiki/Store_of_value#Money_as_a_st...
A good store of value is scarce, durable, transferable and divisible - and I think most people agree that you compromise scarcity to get price stability.
We don’t have to take anyone’s word on this though you can just look at what endowments and wealth funds hold to see what people believe are the best stores of value: https://www.nbim.no/en/the-fund/investments/#/
A double speed attack doesn’t need anything particularly dystopian to happen. It doesn’t even need to result in a large transaction just someone deciding to short BTC and briefly having the computing power to destroy it. Even just a creditable attempt that fails could completely undermine it.
The only way around that is to constantly spend more money on hashing power than any attacker, but that cost is effectively unbound. Trying to stop some random billionaire doing it for the lulz means sky high transaction fees forever. No problem for an actual currency in widespread use, but a serious issue for a hypothetical store of value which needs constant investment just to break even.