While there is only one iOS App Store, there are actually three ways to browse it:

1. Through iTunes on a desktop, or laptop
2. Through the App Store app on an iPhone
3. Through the App Store app on an iPad

Apple has set this up so that an app can be featured in one storefront, but not the other, despite the fact that they're all the same App Store.

To avoid ambiguity, the featured report differentiates between storefronts when displaying the location in which an app is featured.