Agreed. I suspect this notion that you incur mental cost from screen-switching comes from those who have not used a tiling window manager. Once you get used to this, a desktop is clumsy/painful to use.

I have the same layout every day: screen 1 is tmux with several xterms, one running vim; screen 2 is the browser; 3 is email; 4 is remote connections; etc.

I constantly toggle alt-1 and alt-2 to jump between vim and the browser and it takes no mental effort. Why not put them side by side? I could, but I prefer full screen.

[Your down-voter could perhaps re-read the guidelines.]