Lots of games give bonuses if you have other games by the same publisher installed. Lots of ad networks reward users for installing apps, I suspect many of the

Lots of games give bonuses if you have other games by the same publisher installed. Lots of ad networks reward users for installing apps, I suspect many of these ad libraries are calling this API for that reason. I just yesterday had a fitness app tell me that Google fit wasn't installed after I'd asked it to link up with Google fit. That was useful.