Instead, the proponents’ argument centered around the idea that the bitcoin market is mature enough to support an ETF, and at present looks similar to markets for other assets which already have such products. The presentation gave several examples of assets that already have ETFs, including crude oil, silver and gold. The presentation specifically tied the idea of futures markets with spot markets, noting that for money substitutes such as gold and silver, this connection between the two can be proven with empirical evidence. Further, this type of price co-integration “is evidence of a well-functioning capital market.”

https://www.coindesk.com/bitcoin-etf-seekers-met-with-sec-monday-in-latest-pitch-for-approval