Is a MainWindow.xib truly needed in iOS application?

Question

Before doing any type of iOS 5.0 development using Xcode 4.2, Xcode has provided a \"MainWindow.xib\" in templates. After downloading and playing with Xcode 4.2 with iOS 5.

Answer 1

I always feel confused about the usage of MainWindow.xib: even with it I still need to set window's rootViewController or addSubview to it. Isn't that information contained in MainWindow.xib ? Why I still need to tell window about that?

So removing MainWindow.xib seems to make sense.