I think it's fairly obvious to say that a good portion of clicks in many Android and iOS games are not intentional.
When my son plays the Angry Birds version with ads, he occasionally clicks the ad without meaning to. My wife has done the same thing (this was before installing an ad block on my phones in annoyance). Multiply that by the millions of people who play these games, and you have a significant number of clicks being registered by people simply trying to hit that pig with a bird.
This reminds me of a number of years ago when Netzero was really $0 for internet and would show a banner/advertisements on the bottom 200px or so of your screen, or when AllAdvantage would pay you something like 40 cents an hour to display banners to you while you surfed the internet. Yes, you're exposing ads to eyeballs, but is the interest really there to justify paying $x.xx per click, when a good portion of those clicks belong to people who not only didn't mean to click the ad, but now are frustrated that they clicked it in the first place and see your product on their screen before going back to their game?
The problem is made worse by game and app makers "strategically" placing ads where they know they'll get a ton of mis-clicks. They're basically sending out trash traffic that has very little hopes of converting to sales.
I can't be alone in thinking this, can I?
I actually work in a company that runs a small side business with writing apps. Most of them are free and only drive money by adds. Actually I don't understand why people download those apps at all. And I have no idea, why anybody should click any of those adds. Still we make some money with it. Enough anyway to keep our devs busy between larger app projects we do for customers or to get new devs into app development.
But then advertising is expensive anyway. Companies pay a lot of money only to have their names and products appear on tv or in magazines. So the main idea here is not necessarily to sell something right away, but to have a first contact and keep a faint memory of you brand name in the users memory.
Just by chance I hit the website of my internet provider today. They offer you up to 150 euro if you get somebody to make a new contract with them. That's what they earn in the first six months with such a contract. Obviously they expect to start making money only after a longer period of time.