[tobr]

There are things that are useful to the extent that they're not inaccurate, but most of it is very incomplete with regards to how most of the music most people enjoy today works. Recorded music is not mentioned, blues tonality is not mentioned, there is no theory of groove or syncopation, and there's nothing about lyrics. Without these things, "music theory" is not useful for studying modern popular music.

Your book recommendation looks quite interesting too, thank you. I'm not sure if Ethan Hein's blog is a great starting place for a beginner, but it's some of the best "theorizing" around recorded music that I know of.