My organization doesn't develop mobile apps, but we provide APIs that power many of the top apps in the "News" categories on the various app stores. We've seen apps that are solely designed to just consume our API reach #1 in categories a few times. And we love to see that.
But, when an app gets popular as described above...? Copycats come out in full force, stealing API keys, decompiling apps for data and info, and other completely nefarious techniques with zero innovation. And they release exact copies of competing applications.
No doubt about it, while "controlled", the app stores are still a wild-wild-west.