More important than typing speed is the ability to use shortcuts. Programming tends to involve short statements and many movements around a file and between files, instead of writing long prose as you would when writing a book.

Being good at using keyboard shortcuts does not necessarily make one a good programmer and vice versa, but it certainly is an advantage to be able to quickly navigate your development environment.

I find that this helps me focus on higher level concepts instead of focusing positioning mouse cursor and clicking on things.