If you have two candidates who you're certain are equally good developers, then obviously the one who types faster will be more marginally more productive. But I wouldn't assume typing speed or style is an accurate proxy for programming ability.
I think it's rather a proxy of how long the person spends writing on a computer. For a programmer more time spent writing generally means more time programming, which means more experience.
I don't think time gains because of faster typing don't even factor into a decision, but broader knowledge/experience does.
