Even if it is useless and I'm not saying it is, it is not illegal or is there regulation for the sale of useless products.
It's not a question of legality, it's a question of commercial viability.
Mined cryptocurrencies perform a monetary function "out of the box" which is that they implement the archetype of a bearer token or "bearer instrument" on an electronic network. You can verify and make use of that monentary function the moment you purchase it, just as you can verify and make use of a copy of Microsoft Windows the moment you purchase it.
On the other hand, a token that is generated arbitrarily by an interested commercial party, that has no software function in its own right nor any monetary function other than its resale value based on a promotional concept directed at a market of a tiny subset of a single wallet.....is of limited market viability and almost 100% risk as far as new investors are concerned.