now Bitcoin price has increased 17.5% in the last 7 days and now the price is $27,750.69, then BTC Domination is 70.9% with Market Cap amount $727,677,130,354, but Ethereum price is currently $644.61 and is down 1.44% from the last 7 days, so I bought Ethereum with all my money (money that I use specifically for investment), because I believe Ethereum price will soon increase very high (bull run) following Bitcoin price movement and of course I will get a very big profit from investing in Ethereum (my target for Ethereum price is $1100-$1400), because I believe if Bitcoin dominance decreases, then it will make the price of altcoin increases (including the price of Ethereum).
Since that I am one of the ETH holders I could say its not a mistake in my own opinion. Perhaps, I suggest not to convert all your money into Ethereum I think it is better to leave still for Bitcoin, because surely the When Bitcoin spike in the market Ethereum will follow as well while Bitcoin price value kicking in the market, that's what I had been thinking actually.