Tbh I think alot of the "thinking" still looks like visible work though. I feel like the article makes it seem a little too much like there's nothing observable, nothing to show or demonstrate, until POOF the code comes out.
But I find that I often need to be doing visible stuff to make progress... Like devising little experiments and running them to check my assumptions about the system (or discover something new about it), and making little incremental changes, running them, using the output to guide the next thing I do... Even occasionally spending the time to write a failing test that I plan to make pass.
So I'm 100% on board with letting managers believe this "80% of the work is invisible" thing... But I think as advice for programmers, it's really important to not get too stuck in your head and spend too much time not kinetically interacting with the system that you're trying to change.