Typing ability is an effect rather than a cause of hacking ability.

It's not so that you can type code quickly. The bottleneck in coding is always the thinking time, or you're using an overly verbose language.

Typing is important because hackers communicate with one another using a keyboard. I've worked with programmers who couldn't type quickly enough to have a comfortable conversation over IM. It's torture.

If you can't type, it's probably because you're not communicating enough. Hacking is not a solitary activity, and it's mostly not coding.