It's actually kind of obvious. If there weren't benefits, people wouldn't use it, and there are some pretty obvious benefits. Why use a directly compiled language instead of a scripting language put through two(?) layers of translation? Why use a language that let's you directly access all features of the platform? etc

Honestly, there are few apps that provide anywhere near the user experience that a native app does (one of those being facebook) and even they opted to switch to native. I've written a graphics intensive phonegap app and... needless to say, that was enough incentive to learn objective-c and I'll never look back. Objective-c is actually an awesome language, it's just tough to learn for most developers coming from a standard dot notation language.