The app is designed for American shows, and therefore displays the American air dates of each episode. The main menu displays a list of shows that it thinks might interest you, along with information about when then next episode will be playing to keep you up to date.
It's important to keep in mind that this app doesn't download any episodes, it just lets you know when they'll be airing. So in that sense, it's kind of like an agenda that you can organize and edit, but can't use to actually watch the shows.
SeriesGuide Show Manager is a useful tool for anyone watching TV shows, especially if you have several going at the same time.