We've had spot ETFs here in Canada for quite some time.
To me, the biggest issue with these products has always been that the underlying assets can't be valued properly. The exchanges aren't regulated to prevent price manipulation through things like wash trading or spoofing.
In order for the SEC to approve it a number of major issuers basically had to agree to some kind of price monitoring system. I'm sure Coinbase is critical to this as they are the only exchange based on the US that isn't prima facie fraudulent.