I'm new to iOS development. I've read through some of the source code I've found online and lots of them does not include a single nib file. All the view seems to be drawn manually from code.
What is the benefits of having/not having a nib file? Why did they choose to create everything from code instead of something you could visualize such as storyboard or *.xib files?
There are very simple nibs like the typical MainWindow.nib, which don't have localized content and can be reproduced with a single line of code. In such cases code is much faster than unarchiving the nib.
There are also highly dynamic layouts which are impossible to describe as a nib.
You should choose the most convenient and efficient way in each particular case. There will always be tradeoffs, just choose wisely.