As someone whose computing career was improved by learning to touch-type in grade school (Mom had been a secretary, saw that these "personal" computers had keyboards, and bludgeoned the high school to let me in to the summer-school typing class) it's not actually the speed that matters - though that does certainly impress people - it's that it's "automatic". If you're not thinking about letters and where they are, you aren't distracted from the entire sentence (or function) you're holding in your head - it just pours out through your hands into the machine.

(Sometimes I joke about how my hands know emacs, not my brain - but if someone asks me what keys I hit for something, my fingers move and then I work backwards from that.)

(And if you're collecting correlations - I have no musical performance talent at all and have spent maybe 10 hours total poking at musical keyboards - for me, typing is all typing, I expect musical keyboarding is a related but parallel thing, not the same thing.)