There are many coins that are ASIC-resistant like VertCoin, but why we should use Bitcoin Gold? What is the main difference?
Explain to newbie why we have so many Bitcoins, Bitcoin Cash, Bitcoin SV, Bitcoin Gold, Bitcoin Diamond and so on. All of them are useless except the real one - Bitcoin (Bitcoin Core).
That's the point. Vertcoin is already ASIC-resistant, and so does Ravencoin. With the various number of altcoins competing against each other in terms of ASIC-resistance, and innovative features, it'll be hard for Bitcoin Gold to get somewhere. Besides, there are many Bitcoin forks in existence which haven't served a real purpose in life. The only one from the list of forks you've mentioned that has some chance of survival is Bitcoin Cash.
Other than that, most Bitcoin forks would die if they cannot provide real uses for the mainstream world. Bitcoin Gold may have ASIC-resistance and privacy, but it would need more than that to stay ahead in the game. The key towards the survival of any cryptocurrency is developer and community support. Hence, if BTG loses those key aspects, it won't have a future at all. Just my opinion
