The way I see it is it's usually just someone trying to cash in on the "hidden gene" idea. Ralph Davis's platty daddy produces normal looking offspring which carry a hidden gene that when combined with a lesser platinum, can create more platty daddies. So in that case, lesser siblings produced from a platty daddy WOULD actually be worth paying extra for. In general though, it's just marketing. Don't pay any attention to it, and don't pay any extra for it.