Update: It appears Apple has done a lot of these things, so thanks!
When you write a Core Animation heavy application, you spend a lot of time implementing code that executes when an animation finishes. Typically, the view controller whose view contains the animating layers implements animationDidStop:finished: and does a series of checks to see which animation finished. This method becomes difficult to manage as the number of animations it handles increases. You must also set the delegate of each animation object and tell them not to remove themselves when finished. You end up writing a lot of code over and over again.
(Disclaimer: These are my (Joe Conway) opinions. Not Aaron Hillegass’ or any of the rest of the Big Nerd Ranch staff.)
When I teach, I always make sure to mention the dot-notation addition to Objective-C 2.0. Then, I make sure to tell the students never to use it ever, ever, ever again. But why? Why this seemingly irrational hatred of dot-notation? Is this a style choice and us “bracketeers” are being hard-headed? The answer is no, we are not being hard-headed, we are keeping our code consistent and maintaining readability.