To find out if AB2 is worth it just watch the commercials for other games that Rovio is showing throughout the game. From restaurant simulations to a hundred different ‘slide finger to break bubbles’, as a software developer of 30+ years it pains me to see the manpower go to waste. Breed dragons, breed monsters, flowers, eggs, islands, blah, blah.
So yea, AB2 is worth it in the grand scheme of things.