By definition perfection is better. For a lot of us perfection isn't attainable but I will always strive for it. I want my quilting experience to be positive and turning out a quilt that isn't as good as I can get it would be frustrating to me. If it's worth doing;g, it's worth doing well.
I also do not understand why anyone would deliberately make a mistake to leave in a quilt. It doesn't make sense; I'm not convinced that's a thing.