Western music theory sucks. It's as if we were still doing arithmetic with Roman numerals... it's a tower of kludges. But there's little point in playing music other people have composed. That's what we have audio recording techology for. (Arguably if you do want to learn someone else's music for some reason, you're better off learning it by ear anyway, and this book recommends memorizing music instead of learning to sight read, IIRC.) So as long as you're improvising/composing your own stuff, you might as well invent your own way to think about it.