Bitcoin is currently dumping as the cryptocurrency developers are looking  to push and promote bitcoin cash equally to bitcoin.
Whereas ethereum is also cashing since past two days. People are eagerly following bitcoin cash now bitcoin is still king of cryptocurrencies.
If i have ETH right at the time, i would have bought bitcoin. I beleive bitcoin will regain its priority in just a month.

For me it's a no, maybe some but not all.  You can collect many potential coins for future purposes. You should still hold ethereum because when it's price rises you will regret it thats why atleast keep some of it and also buy some bitcoin. It's a win win situation if you own both of that cryptocurrency.