Some just want for pets, like me. I like creating color mixes with my chickens, and just because it's a "poor example" doesn't mean it isn't a good chicken.
I have mix breeds too. Would i sell them as anything but pet quality? No. But the thing is. I do sell them as pets and hatching eggs for backyard layers. I don't see anything wrong with it but I do see the point if I was a breeder, esspecially for show or breeding quality birds.