Bitcoin is the real Bitcoin! Bitcoin Gold is just a fork wherefore I can't find another use case than as insurance on BTC. When something bad happens to BTC because of mining centralization, BTG could take its place.

I believe in markets and since the market values 1 to 2 percent of the total value to BTG I think the market expects that there is only 1 or 2 percent chance that this will happen.

Even in case of extreme miner centralization I think the chance that the code for another mining algorithm get forked into BTC is way bigger than the chance that BTG takes over.