SEC will not aprove a ETF that will buy actual bitcoins. the one they might with a 10% change aprove is one that is betting on the price with futures.
It's impossible to say that up front. The SEC is worried about how the demand and thus the majority of the volumes are generated in Asia.
In the end, I don't know why everyone keeps focusing so much on the SEC. People really made the SEC look like a Bitcoin kingpin. It's just one regulator covering just the US. If you take into consideration that the far majority of the demand is coming from Asia, it makes way more sense to have regulators there approve an actual coin backed fund.
An Asian ETF would logically generate more investor interest than one launched within the US. If US institutions were really that horny on coin backed funds, they would literally flood Coinbase with their index fund, but it's not happening. Perhaps a clear sign that the interest might not be there?
By the time the SEC finally approves an ETF, you'll have various ETF's on the market all competing for their cut of the volume pie.