But the question of what is a "security" has been clearly answered in 1946:

> For purposes of the Securities Act, an investment contract (undefined by the Act) means a contract, transaction, or scheme whereby a person invests his money in a common enterprise and is led to expect profits solely from the efforts of the promoter or a third party, it being immaterial whether the shares in the enterprise are evidenced by formal certificates or by nominal interests in the physical assets employed in the enterprise.

A lot of these coins are attached to some such scheme by a 3rd party, therefore they should be considered securities. This may even apply to most NFTs.

Source: https://supreme.justia.com/cases/federal/us/328/293/