Ethereum is not a threat to Bitcoin as it performs very different functions. Ethereum is a platform for the functioning of smart contracts and even if ever the Ethereum capitalization becomes more than bitcoin, in the cryptocurrency market nothing will change and each coin will be used for its purpose.
2019 looks bright for Ethereum as HTC Blockchain Phone Exodus 1(which is only accepting Bitcoin and Ethereum) has already been launched in advance on December 12, 2018, and is ready for purchase.
As the market is also down right now, the price of all the cryptocurrency as declined. According to CoinSwitch
btc to eth converter, the price of 1 BTC is equivalent to 38.32 ETH. As the price of ETH is down, it is good to buy Ethereum now and hold it for a long time.