I type at least that fast, and the keyboard is still a bottleneck for me sometimes. When using emacs/vim and primarily using the keyboard, there are extra gain

I type at least that fast, and the keyboard is still a bottleneck for me sometimes. When using emacs/vim and primarily using the keyboard, there are extra gains to be had by typing faster, because you can use keyboard shortcuts to navigate, find text, etc. Unless you're playing a videogame, it's unlikely that you'll practice or improve on your mouse coordination and make significant gains there.