That is 7 days worth of pure hell in the crypto markets--yikes!

I agree that it's probably a good buying opportunity for bitcoin, but I don't have any faith in BCH so I'd stay away from that one for the long-term.  Some of the other ones that might be useful in the future might be worth buying, but I still think bitcoin is where it's at. 

However, even with Bitcoin Cash, you probably could make a decent profit by trading it short-term.  I don't think it's dead or dying even if I lack the aforementioned faith in it.  Other investors probably DO have faith in it and thus will cause it to rebound.  I keep saying this, and it hurts:  If only I had money to buy!!  This is the kind of volatility that can make you big bucks by day trading.