I type about 3x faster* than some of my co-workers, and I can tell when I'm working with them that it does make a difference.<p>They don't even try do to exploratory programming.  In cases where I would just write some throwaway code for an experiment, or turn to a REPL session to answer a question in a few seconds, they start leafing through documentation or Googling for someone else who knows the answer.  I write and re-write code <i>while</i> I'm thinking; once they start writing they are unwilling to change their minds mid-stream.  Even in normal "batch" programming, it means that instead of 5 minutes of thought followed by 1 minute of typing, they have 5 minutes of thought followed by 3 minutes of typing - so they take longer to resume their stream of thought, and spend slightly less time thinking overall.<p>*I type about 60wpm which is not especially fast, it's just that I work with some people who are not touch-typists.