When you are drilling new keys but you absolutely do not want to look at the layout map that shows the keys you are supposed to know already.
I honestly think that touch typing on QWERTY is a bad idea, those contortions you need to go fast will just give you RSI sooner or later.
I also learned touch typing with colemak mod-DH and that kind of works, but now I’m running into the fact that standard keyboards are very asymmetrical. Unfortunately I can’t seem to find a split board with an F row.
I almost feel like my piano training has kicked in with my QWERTY technique. I almost move my left hand above my right sometimes to hit certain keys. It’s definitely a lost cause and you are totally right: we know so much more about ergonomics now that if you are going to learn to touch type at this point, you might as well learn an alternative layout.