When those plastic corks first started appearing, and people said they were good because they both preserve the wine better and save cork. Well, now as they catch on more and more, it turns out that if we stop using cork, it's going to really mess with a lot of people and animals. So, now you want to use real corks again. FYI. This is a lot like that whole "eggs are good for you," "no, eggs are bad for you again" debacle. Or the way the fat in avocados is "good" fat. It just gets so confusing that you stop caring.