I dont really see a problem with the grading system to differentiate quality in variants.. however, plastering a fancy name on a fairly common ray (see TFDfish) in order to inflate the price is pretty lame.
If we didn't differentiate variants in dogs, it might be the same issue..
"I have a brindle dane"..
"No, you just have a great dane, they all the same"..
"well no mine is a brindle its a bit different, and my friend has a reverse brindle!"..
"Nope, nope.. all great danes are just great danes no difference in quality, some just might have different colors"..
It really is just up to the buyer if they want to pay more or not.. just as long as it's not used as a deception tactic