This is absolute horse ****. It makes zero difference to any customer what ISO you shoot at, unless you're shooting for a client who cares more about the technical things that don't matter rather than caring about the artistry of a photograph, at which point I would fire said client. Furthermore, more noise absolutely does not equal out to a poor quality photograph. Bad lighting, poor composition, lack of color harmony, a poor understanding of your subject and bad editing is what creates poor quality in a photograph. BTW, I shoot weddings with a Canon 5D from 2006, often set to ISO 800 or higher, charge $2k+ for a wedding, and guess what? Clients love their photos. Real world experience outmatches your strawman speculations any day, and real artistry and talent will always prevail over meaningless technical bull crap. Next.