Some group of people has argued we will experience another high surge in Bitcoin Price early 2019 when ETF get approved while some said ETF does not have any crucial role in influencing Bitcoin Price positively. From the little experience i have acquired since i started trading on Cryptocurrencies , i have got to realize price Predictions has never been any effective .The underlying theory of Bitcoin price determinants still remain a mystery unlike in traditional market unless someone got a Crystal ball. lols. Some experts has made lots of wrong prediction in the past.
First of all, there is no assurance that bitcoin ETFs will be approved in early 2019. It may or may not happen so always have a contingency plan ready if you are banking on this news.
Secondly, try to understand what type of ETFs are being reviewed by SEC. Are they synthetic or Physical? If they are synthetic, that means, actual bitcoins will not be bought from the market. That won't change the current demand and hence no impact will be seen in the market. But if the the ETF is a physical one like, Winklevoss ETF, then you can certainly expect some impact in the market, because in this case, physical bitcoins will be purchased from the market which will increase the demand and take it up to another notch higher!
So based on the type of the ETF, you can expect some impact! However, I don't see any hope of the ETFs being approved anytime soon in 2019 as SEC is still very skeptical about these proposals. So don't bank on this just as of now!