It's not about the coins, it's about the intent. If you go to the SEC and say "I'm going to sell pieces of paper of dubious actual value as securities," they'll be interested. The mechanism that the securities use is not important.
The unlawful part is not the technology, it's how the securities are sold. If you sell something that looks like a security, sounds like a security, and smells like a security, and you're violating regulations around securities, then yes, it's potentially unlawful.
The unlawful part is not the technology, it's how the securities are sold. If you sell something that looks like a security, sounds like a security, and smells like a security, and you're violating regulations around securities, then yes, it's potentially unlawful.