According to Nouriel Roubini: "an illegal cartel of service providers who are safe from price competition and in a position to gouge their customers.
Dentacoin is a ridiculous cryptocurrency that can be spent only
on dental services (and which almost no dentist actually accepts). It
would be hard to come up with a better illustration of why business
cartels are illegal in all civilized countries.
Of course, the crypto-cartels would counter that customers who incur
the cost of buying a token will benefit if that token appreciates in value.
But this makes no sense. If the price of the token rises above the
market value of the good or service being provided, then no one would
buy the token. The only plausible reason for forcing the use of a token,
then, is to hike prices or bilk investors."