My initial though on Bitcoin Options was that, It would stabilise the prices, but now I can clearly see that it is been used to manipulate prices before settlement day. Recent example: BTC option maturity was on 10 June 2018. You know what happened.
I dont know exactly what ETFs would do, One thing is sure, it will increase liquidity due to money coming in from institutional investors. But It has to grow to the level where price manipulation becomes impossible.
Lets see where it goes. I am bullish on Bitcoin.