Completely useless!
All this app does is let you customize the different interfaces it has, but what’s the point if you can’t even see the code documentation? I really don’t understand why any developer, or literally anyone at all, would even download this? Unless you want to quickly see a UI component without going into Xcode, or to spend lots of time Googling it, it should at least have the source code so you can quickly apply it to your app. Thus saving you time and effort.