Also, as a vim user, modes are completely fine and I do not believe that modes slow me down. I’m not sure why the author is so insistent on this point.
Intuitively having to press more keys in order to accomplish an action sounds like it would be slower than a single key combo. Of course this fails to account for the fact that pressing something like Option+Fn+Backspace to forward-delete a word is far more awkward than f-d and therefore takes longer.