Nothing in this is new or unexpected. See Ripptoe and Kilgore's Practical Programming for Strength Training for a comprehensive guide in deciding how much weight to lift how many times.
As other posters have mentioned, it's well known that high-rep lifting will increase muscle mass, and that's what bodybuilders do. However, powerlifters don't care about anything but strength, so they use low reps, just as Starting Strength recommends.
So if strength is your main concern, like it is for Rippetoe and Kilgore, you would follow their recommendation. A higher number of reps with lower weight is certainly not just as good for strength development.
Strength increase and muscle growth go hand in hand.