I think the SEC's concern is that a public market exists for all sorts of different crypto currencies and contracts, and scams, and they are struggling to find ways to control them. A decade or so ago the SEC was not fully empowered as Wall Street turned simple mortgage bonds into complex securities that were rated to be of the highest quality by rating agencies, yet were of high risk of default.

SEC endorsement of any cryptocurrency or token, or fund, would be an amazing thing but they are in no rush to approve these crypto funds as legit securities, then be blamed if a national crash occurred.