Nothing is tangential with regard to CAGED, all is of intrinsic foundational essence. It was instrumental in creating The Big Bang and is the key to successful biological ecosystems, not to mention its widespread use as a dessert topping. Also somewhat useful with guitars. I've done it. A band that I was with did "Can't Let Go" from Car Wheels on a Gravel Road by Lucinda Williams. I don't remember the original key on the Lucinda record off the top of my head, but to fit her range, our lead vocalist decided on Bb. I was in standard tuning, and really wanted to bounce off the open A string for certain passages. So, capo @ first fret, with a slide. Thanks. Alrighty then, back on me head, break's over.