They possibly could/should add the qualifier of obnoxious ads. Many mobile ads are extremely obnoxious. Especially the ones that hide the "X" or place several "X"s in the interface so it's hard to tell where exactly to tap to get the ad to go away. This game is pretty classy and subtle in comparison. Kind of how Hacker News itself is an ad for YCombinator.

it's cute how you've come to accept the less obnoxious ads as okay. it appears the obnoxious ads have served their purpose.