That's the thing, you can't pay to be a contest winner[/]. Since I've been on NB, I've seen admins simply use "cyan usergroup". They hardly go out their way to say, "I've got to place you in the 1st place contest winner usergroup".
If it's the cyan/large ava you're paying for (I'm sure we both agree that it'll be extremely illogical to buy an award), why that title instead of "cyan user"? The title reads: 1st Place Contest Winners.
We'll be paying for cyan, not to be a contest winner. The difference you're curious about is the fact they didn't win anything.
But, but! If they have to win to even be able to pay for it, the title then makes much more sense.
Not to mention how illogical it'd be to have anyone be able to buy it. If anyone can buy it, why restrict gifting it to people? Anyone can have it after all. Many users would be content with just cyan, so I wouldn't be surprised if the interests in contest dropped to an unprecedented low. On the other hand, interest could rise if a contest meant keeping cyan as long as you can pay for it.
Then we get to the extreme lost of value on the cyan, it's no longer a 1st place prize (again - this brings us back to the implications of the title, how in the world is it a usergoup for contest winners if I'm not a contest winner?).
Sure, they'll maybe gain much more money (though I do have my doubts on this, I mean why create simply for money when the only difference between cyan and premium is the usernsame color?? In fact! why not just add the color cyan as an optional color in the premium permission groups??), but at the price of completely destroying any merit the contest system still have.
I actually have much faith that they're not this illogical.