I understood the purpose to be identifying "immersive" (emacs-like) programs that sick you in and trigger a mental context-switch, versus vim-like transient too

I understood the purpose to be identifying "immersive" (emacs-like) programs that sick you in and trigger a mental context-switch, versus vim-like transient tools that you pick up and put down as you need them, all without leaving the mental "place" you're in. He then argues that this effect is significant and wonders how we can get less immersive software.