I don't know if you understand what ETF really means. This is huge for the non-geek investor to hold bitcoin. It will be possible for anyone to go into their local banks, and tell the employee to but you some COIN shares, anyone can do this. Once people get gains with that, it will spread, everyone can get in with no technical knowledge about bitcoin in a safe, regulated way. So all those old millionaires, or your regular person that just wants to hold BTC but isn't really sure how to do it, will be able to get in thanks to the COIN shares. Of course I personally recommend people to learn how to buy and hold actual BTC, but we can expect everyone to do that and COIN will be 'it', the missing link to get the average investor that is not into cryptography/computer stuff. This means potentially billions of increase on the marketcap. With some time price going x10 is perfectly plausible. How long it will take? I don't know, but it opens the door for that possibility to happen.
I think even without ETF Bitcoin will reach $10,000 if we are talking about the long term price of BTC. Having all the issue with Bitcoin fixed or solved, Bitcoin will eventually get there at $10,000 a piece. But if ETF will be approved, it will hasten Bitcoin to reach that price because of the massive investment pouring in the Bitcoin economy.
What issues do you mean? IMO bitcoin can definitely reach that price, not through "fixing it's issues", but rather through more adoption. Compared to the 2009 - 2012 era, both price and adoption have increased substantially.
I agree that the ETF is a very significant step in terms of bitcoin because non-technical investors can finally get into it. Personally I'd really like to introduce bitcoin to some of my older family and friends, but they're not very experienced with new technology so there's a high possibility that they might lose it all due to carelessness.
The ETF provides a way for the not-so-techy people to invest in bitcoin. Yes, you could argue that the Winklevoss twins' system could also be hacked like any other exchange, but that shouldn't really be the investor's problem. Since their target audience are non-technical people, their company should cover all the security measures needed. If not, there will be a lot of angry investors and that'll be a loss for everyone involved.