If you know C and you get properly acquainted with Objective-C, you will realise that Apple succeeded in making people write large C code without hating it or getting into trouble. People say, and I agree, that learning Functional Programming (FP) makes you a better programmer even if you were to go back to non-FP languages. I think the same thing can be said of programming for iOS using Apple provider toolkits. Learning to code iOS application yields much more than solid applications, it also teaches you how to be a better programmer.