ETH is also a utility token and the SEC has said they would not interfere if the ETH ICO was today because it complies with their rule. So Dusk should be fine indeed.
As far as I remember one of the SEC officials said something along the lines of Ethereum may have been a security at some point in history, but because of the current level of decentralization it is not a security at this time.
Crypto currency, utility token, security token... To the SEC it is irrelevant what the asset is called. In order to determine whether it is a security they perform a duck test (does it look like a duck, quack like a duck, walk like a duck? then it probably is a duck), more specifically the Howey test.
In order for a financial instrument to be dubbed a security and fall under the purview of the SEC, the instrument must meet these four criteria:
It must be an investment of money
With an expectation of profit
In a common enterprise
With the profit to be generated by a third party.
But, since DUSK is not sold to US citizens this may be an irrelevant issue.
