there is no way that Bitcoin Cash will go anywhere.. honestly I don't see what people are seeing in these forked Bitcoin versions, the only way any of them has any substantial chances of survival is if Bitcoin will fail. What are the chances for Bitcoin to fail? They don't offer anything different than Bitcoin so there is no other reason to buy Bitcoin Cash unless you want to replace Bitcoin. They are only a good investment if you want to hedge yourself for a potential Bitcoin fail, which most likely will not happen. Bitcoin has survived much worse and that's the reason it is still number one. Do yourself a favor and invest in something that offers more perspectives and more value than simply some forked and copied version of original chains.
There are no certainties but recent events show that it could prove valuable. Its all speculation off course. How do you know if bitcoin wouldn't fail or not? Slow confirmations, increasing fees may cripple it. Don't forget also that there is only a set number of Bitcoins, people will look to alternatives if they cannot get their hands on "cheap" bitcoins. And so far BCH is proving to be more valuable than other altcoins, riding on he bitcoin name alone.