I think it's because of the App Store's roots in iTunes. Searching for media—music, let's say—usually requires you to know the name of the artist, album, or son

I think it's because of the App Store's roots in iTunes. Searching for media—music, let's say—usually requires you to know the name of the artist, album, or song. How rarely does someone know the name or developer of an app? If I were to search for music in the same way I search for apps, I'd never find anything I was really looking for. The terms are too broad. However, searching for music (even if using overly broad search terms) at least lets you preview a song, so you can judge if you're about to make a good purchase.