It was for the Mac Pro trashcan which was a compact design. Although Apple uses odd security screws in all their products, their pursuit of thinness and compac

It was for the Mac Pro trashcan which was a compact design. Although Apple uses odd security screws in all their products, their pursuit of thinness and compactness also probably leads them to need precisely manufactured small parts. Of course if the Mac Pro had just used the old Mac Pro design or the previous Power Mac tower designs, perhaps the parts for a tower case might have been easier to find...