The guilds I have belonged to have quilt shows to raise money. That money is used to pay for speakers and classes. Also to showcase quilts and educate the public. I think several categories is good and definitely let people select whether they want their quilt judged.
So I entered to support the guild, and had decided to have my quilts judged with some trepidation. I have found it to be a positive experience. If someone is commenting negatively about quilts during the show it is a reflection on them, not the show.