I think it's a lot faster than keyboard / mouse, mostly because of how little moving of the cursor you have to do.

Could be I was slow to begin with, not super efficient with vim or emacs.

Also, "editing" is the fastest part for me, due to "bring" and "change". So little movement.

For the former ("programming"), there are many commands that can be used to rapidly output code. For example, a user can say "funky hello world" to get something like

function helloWorld() {

}

But if you're trying to edit code that already exists, it can be a challenge to do so without a mouse and keyboard, in part because you need to do a lot of navigation.

I personally believe Cursorless solves that problem better than a keyboard and mouse, but I have to imagine I'm a bit biased on that point :)