Gamification can be used to promote your marketing efforts, but this should be a secondary function. If your app is used for task management or exercise tracking, reward users for their real-world accomplishments, and have some secondary rewards for getting others users on-board. If your app is used for listening to podcasts, don't give them a "Playlist Creator" badge, nobody cares about that.
I'm also not sure how well gamification is going to address the problem of "users don’t use many apps for very long and in fact only 25% of the apps survive after 3 months." How often do people play full-fledged video games for longer than three months? In the long run, motivation from gameplay is a gimmick, and I don't see a lot of people caring about their level or trophy collection on some app enough to change whether or not they continue using it. In fact if the gamification managed to give the user a lot of reward early-on, but doesn't manage to keep it up (which is really hard to do—again, think about video games growing tiresome) the user could actually be pushed away from continued use. The proposed solution compounds the problem.
Users don't want to feel rewarded for something that's probably wasting their time. They want to know that the action itself is useful. If your app can't do that, how will you retain users? I guess there are still a lot of people are willing to use pointless apps that track which Wikipedia articles they read and give them a gold star, but most people aren't.
