We don't need any ETF, and the average Joe doesn't even know what is ETF. Go in the street to ask about, you will maybe find 2% of people who know what you're talking about. So I don't see how it can help with the mainstream adoption. Only the Bitcoiners care about ETF with the hope to see any accepted, and it's not to get Bitcoin recognized, it's just a matter to see the price jumping to make more profits.
#FollowTheMoney