Imagine having to look at your mouse every time you clicked on something. Now imagine you no longer have to do that.
If you're really curious, just learn to touch type and find out. It doesn't take all that long if you're already a solid typist. I'd be fascinated to read an article from someone who learned how to touch type and thought it was a waste of time.
OK so terminology: touchtype to me means that you learn the fingering the keyboard in a specific way. Not just that you can type by not looking at the keyboard. I can do that. I just never bothered with the "correct fingering".