Samsung has a history of working with creators and embedding them into Galaxy Devices. With the first Galaxy Tab, Samsung swung a deal with Zinio (who until that point only supported Apple) to get magazines as part of the Reader's Hub. Currently, Samsung is partnered with Flipboard. Galaxy Apps is your doorway to other partnered content for your Galaxy device that isn't preloaded.
Previous content providers like TripAdvisor and Gameloft (Asphalt games) are found at Galaxy Apps. New partnered content includes Kindle software. The Samsung version of the Kindle software accesses your regular account and gets you one free book a month if you also log in with your Samsung account. They have 4 picks to range across genres and hey - who doesn't like a free book? There are also exclusive games and gifts. The gifts (Marvel, Bitcasa, Box) are 3 months of premium service - long enough to really see if you will use the service.
Samsung Apps used to point to the Play Store; with Galaxy Apps everything stays in the store. This will help areas that Google doesn't provide a lot of service to...yet.