People could just play the game over and over again and farm AP like there was no tomorrow. They'd eventually find ways of hacking into the game and gaining points quickly, and we'd have a whole new array of rule-breakers for the mods to keep track of.
You might have posted this here but that's alright. In AGv3 from what I've read you will gain achievements on your profile for playing games and such. Gaming participation or something like that.