K10D focus mode: Does it matter?
If the camera has the ability to use a different spot or the outer points are used by the camera to guage the correct OVERALL focus (like 5 point mode in the K-m)then it will slow up focus time and also could allow the camera to decide other than the center spot is correct and shift focus to something you may not want. Can't count how many times we have seen shots that people are having trouble with and from the photo we can see that the camera picked a focus spot in the background because the camera was not set to use the central spot.
There are many times where having multiple active AF spots are good but not where you have a clearly defined subject in the center of the field. You don't want multiple spots if you are shooting most animals in the wild with telephotos.
Multiple AF points is generally good for WA shots so the camera can judge the best overall focus, especially where you don't have a well defined central subject.
Canon made a big deal in the later fim days with their 45 point eye-controlled focus. Unfortunately many nature shooters were losing shots because their eye was shifting some during the shooting process and it was picking a new point as the shot was fired. So most of them turned of eye-control and changed the camera mode to 11 point AF, which is why most Canon no longer have eye-control and usually have 11 points or less.
The old Pentax PZ-1p had only one point and was very fast as a result. As long as your shooting did not benefit from having more points. But the reviewers whined about the "primitive" AF system and so Pentax went to multiple points in the ZX/MZ series and the DSLRs.
Single point AF is the fastest mode you can use. The camera only has to decide the focus and not what point to use.