Something can be useful and a security, according to the SEC. They published an Investor Bulletin yesterday saying as much:

"A virtual currency is a digital representation of value that can be digitally traded and functions as a medium of exchange, unit of account, or store of value. Virtual tokens or coins may represent other rights as well. Accordingly, in certain cases, the tokens or coins will be securities and may not be lawfully sold without registration with the SEC or pursuant to an exemption from registration."

From: https://www.investor.gov/additional-resources/news-alerts/al...