Oh man, all the questions you just asked only highlight exactly why an MBA is so beneficial for mid-career people haha! I'm an adult student doing concurrent CS and business degrees after a long time dabbling in both, and in both cases the value of college was in the things I wouldn't have thought to learn or wouldn't have thought were valuable, especially in places where the signal-to-noise ratio is really low and snake oil is everywhere, like the marketing example you just gave.

Just as a small example, why do you need to read financial report at all? Because that is the language of investors and managers. Why read financial reports for some random company? Benchmarking, so you can tell investors and stakeholders "this is how well we are doing vs comparable companies." A template generator won't help you with this kind of analysis, and those services you mention won't help you if you can't really understand them.

I'm not saying you need an MBA to be a good business person, and I felt like my BBA (which I'm told is mostly the same material as an MBA, at least at my school) only confirmed that my instincts and self-learning after 8 years in the workforce was pretty good...but man, those little bits I didn't know and hadn't thought to learn (especially around finance and proper marketing) were the ones that have ended up mattering the most.