This new section lets users browse apps by categories in a more appealing way. Previously, users had to click on a 'categories' button in the upper-left hand corner and then click the drop down list. Categories are the same as before and Apple claims each category features "carefully selected content updated continually by our editors."
This is yet another move that Apple has made in an effort to increase the discovery of apps in its App Store. iOS 8 will be bringing more changes for the way that users seek apps through an improved searching algorithm, a new explore tab, and much more.