While that's a fair comment, the services being described here really shouldn't be affected: there is no excuse for, say, TapJoy, to mimic the App Store (and I doubt they are doing it, although I haven't seen their UI in a while)... it wouldn't even be optimal for their mission and if they or someone in a similar position is doing so they should probably look at their layout again.
However, I will then point out that the distinction you are drawing can get somewhat vague: just because you aren't accepting money, doesn't mean users aren't now confused because they think they are using the App Store's interface; as an example, they might have expectations such as trusting the validity of the reviews and ratings being shown.