> Comfort greatly is noticeable if you’re transcripting at high speeds frequently (typing tests) but is otherwise questionable.

When I'm writing something that doesn't require a lot of cognitive overhead (typically chatting online, when I may have a lot to say but it's not particularly intellectually demanding and doesn't require a lot of precision or proofreading) I can reach pretty high WPMs.

I'm not convinced that typing speed is always brain-bound outside of typing tests. If I'm telling you about my day at work I'm pretty sure I can just "stream-of-consciousness" directly through the keyboard with very little overhead, especially if I do it in my native French.