I've heard the argument many times that the store of value principle of BTC has been proven by the fact that it has retained its price more than other coins during this tremendous market decline. However, I suspect that this is actually due to BTC having a significantly higher market capitalization than other coins.
Since BCH has 3.2% of BTC's market cap, it's easier to make the price go up or down given the same amount of money. When a whale puts 1 billion into BCH, it will impact the price of the coin drastically more than if they were to place their money into BTC.
We see this evidenced by the fact that BCH usually falls and rises at a higher percentage rate than BTC does. (This is a trend among most coins in the market and not specific to BCH.)
The above chart is the price, in BTC, needed to purchase 1 BCH. We see that as the market cap, of crypto in general, rises, so too does the value of BCH against BTC. Furthermore, when BTC rises in percentage (of dollar value), BCH usually will rise in a higher percent. The inverse is also true during the decline of a crypto market.
If it's true that higher market cap adds to higher price stability, then it implies that BCH, assuming an equal market cap as BTC, would do just as well in retaining value without it being hailed as a store of value only commodity. It would have just as stable of a price as BTC and just as much hashrate (justified by the price), but it would also be much more liquid as transactions are nearly free. The liquidity alone would add great utility value to the coin and it would still retain the strength of all other properties. BCH under these conditions would be an excellent store of value but it would also offer better liquidity which would not take away from the security of the coin or its effectiveness as a store of value.