Eric Balchunas: "The most successful ETF launch is BTC, $17.7 billion.

Gold ETFs represent 1% of the total gold market cap (and I think we can all agree that they have had a positive impact on the gold price). Bitcoin ETFs already represent 5% of the total BTC market cap and that's after only 9 months of existence, while gold ETFs have been around for 22 years."