Coinbase has been extremely conservative in which digital assets it supports (viz., only Bitcoin, Litecoin, Ethereum, and Bitcoin Cash). None of these are securities.
Eth used an ICO.
Still not a security as it's not intended as stake in a business
> Still not a security as it's not intended as stake in a business
What matters is if the expectation of profit comes from the efforts of a promoter or third party, not whether the investment is a share of a business.
When Ethereum ICO'ed it definitely met the Howey test for securities criteria. The SEC even stated that.