It is Mainly for beginners or novices looking to better understand the concepts and the hows involved, however it is also a good reference for intermediate and above model railroaders.
Sure, you could just make something up when faced with the Whats, Hows and Whys, but it would be better still to actually determine a response in which you genuinely believe, even if that belief is newfound, and even if that belief is shrouded in mystery or fantasy.