French cuffs (or double cuffs as they are also sometimes referred to) were invented so that when soiled they could be folded over to present a clean appearance. This was, of course, back in the days when a shirt might see more than a "few days" service before it went to the laundry. As at the "first" wear of the cuffs they were folded inside the sleeve, folding them back might give the impression that you weren't wearing a fresh shirt unless, of course, the cuffs were ironed back. Nowadays I doubt anyone would notice, or even understand, the significance of an un-ironed French cuff.