It is a good point you make about brewing to style, like you don't want to brew a particular style and that's fine. But the real value of having the beer judged in a competition has little to do with your style. Category 23 (sucks to judge) is specialty beer, where pretty much anything goes.
http://www.bjcp.org/2008styles/style23.php The value of the competition is what they perceive in the aroma, flavor, mouthfeel, appearance, overall impression of the beer.
And I never once said the only way you can become a better brewer is to enter a competition. I said, the best way to get unbiased feedback (unbiased because they don't know you or know your beer, all of the judging is blind, the judges only know the category the beer was entered) about your beer is from a competition, what you do with the feedback is up to you.