Maybe I'm misunderstanding, but I think I mean something else. I'm talking about this phenomenon:

A software project is using an open source licence. And app gets made for Android, and because of culture or GPL, the app is open source, too. But on Google Play, the app costs money, contains ads, or there is sub-features, that you only get if you pay a (one time/monthly) fee.

But because it's trivial to sideload on Android, I can just get the app from github (or from the open source app store FDroid) and install it myself, for free. No ads, no locked content.