Basically they are damaged right after the strike. Third party graders consider them just normal coins. But to a true collector, even if they are a variety, they are undesirable to them. Also TPG don't take into account of die state when grading coins. So the buyer needs to know what they are buying before bidding on them. If the images are not showing you what you want to see, then pass on it. Buy the best coin you can find, and don't settle for a problem coin. (you will regret not doing so when you try to sell them.