According to a survey conducted by Bitwise (who made an ETF proposal 2 weeks ago), 58% of US investors would prefer to invest in BTC via an ETF.
https://www.newsbtc.com/2019/01/23/58-of-us-investors-would-invest-in-bitcoin-via-etf-major-hedge-fund/
"the survey saw participation from 150 financial advisors in the US market. When asked what would make them allocate Bitcoin in their client portfolios, 54% of them said “better regulations” and 35% said “the launch of an ETF.”
This is from Bitwise :
https://offthechain.substack.com/p/crypto-etf-101