Yeah, it's easier -- but flash games are rather pointless. Does anyone actually make money selling flash games? You'd be better off learning Cocos2d and developing something that actually makes money, such as an app.
I agree that the app store has more potential for making big money, but there is also a good chance you'll make very little (http://www.dilbert.com/2011-02-12/).
Of course you don't really need to choose, you can make your game for both flash & mobiles :)
I hear FarmVille makes some money.
And game development for iOS and Android is perfectly viable in flash since AIR 2.6 and specially 2.7. There are a few features that are ok in PC that kill the performance in mobile, but for the most part you can make anything you want with flash for mobile and have good performance. Talking form my own experience.
I agree that the app store has more potential for making big money, but there is also a good chance you'll make very little (http://www.dilbert.com/2011-02-12/).
Of course you don't really need to choose, you can make your game for both flash & mobiles :)