I've read those articles, but I still don't see why you need dynamic features to implement the responder chain. UIResponder can have implementations of all the

I've read those articles, but I still don't see why you need dynamic features to implement the responder chain. UIResponder can have implementations of all the methods that return NO. You override whichever you want to, and return YES. Then, instead of checking if a selector exists and then invoking it, the system just calls the method, and if it returns NO, it moves on to the next responder in the chain. What am I missing?