I show APHA and would never buy a horse solely based on color. Anyone running their breeding program solely for "color" I would run far and fast from. Although I do have my color preferences, I buy the best talent and build I can for my money. If I purchased for color or names on a paper, I'd never have the success that I have and who knows what kind of designer junk would in the pasture.
Also... Any registry can only be made up of the quality that is brought to them.