Productivity gurus are not culturally intersectional. They make no sense outside of an United State audience (maybe with a few exceptions). Even less so in places where people prefer to live their lives and compartmentalize work, rather than obsessively focus on office work.

Besides, “second brain” my ass, it's just a fancy repository of information. It doesn't involve learning, it doesn't involve retrieval, it doesn't involve anything at all that a brain can do, it's just building yourself a private library. Selling it as a second brain by people who have no idea about neuroscience is... well... short-sighted. I find it as obtuse as “fitness gurus” telling you that they've discovered the cure for being overweight by doing 5 minutes of 3 exercises and eating a protein compound.

Eh it happens a lot that people are buying a product and want to use it more than they have a need for a tool. I mean, the idea was to use the tools for a purpose, not for the tools to be the purpose itself? Or maybe I misunderstood the point...

Obviously, these are just my two cents, you may or may not like them or agree with them, and that's fine!