Why on earth would you buy a wide quad if you plan on taking it GNCC racing? There are much better choices.
Well not trying to piss anyone off, but here is my analysis:
I guess you could ask a person who only rides dunes why they would buy a MX bike, when a Raptor 700R may be a better duner? Why a guy races an Outlaw in the WORCS program, or why all Baja riders don't ride DS650's? It's generally because if they are going to spend 7 to 8K on a quad, most people buy whatever is the hotest new bike to have. I remeber seeing a ton of 04 YFZ's for sale in 05 because it was the bike to have in 04 but they intended to only trail ride with it! Only to find out it was too small, uncomfortable, no reverse, hard thumb throttle, and a terribly hard MX seat. Well it'sa race bike, but even though it didn't suit their needs they still bought it! They only reason they bought it was they had to have the hot new bike and be seen on it. People are concerned with image more then function, why else is there so many 5 ft. tall women driving Hummers? Okay, I'm off my soapbox sorry...so to answer your question.
People buy what appeals to them at that moment for whatever reason it may be. End of story!