Or it could be that those are examples from his own code and he simply copied and pasted them without thinking that they might not be as useful as contriving more simple examples.
Actually, yes. At the end of his "tutorial", he explains in more succinct words what those functions do, and he use simpler examples. I suggest that instead of hiding them somewhere at the end in the middle of a paragraph, he put them in emphasis at the begin of the document.
Do you have some examples you can suggest?