Curved awls are very helpful for creating holes for stitching rounded or curved leather pieces together (as opposed to those that are flat). When joining two pieces that will be over a curved surface, the curved awls create an opening that will more naturally reflect the curve of the final stitch, allowing for tighter stitching and more overall control.
These awls also work well when you don’t want to fully penetrate the leather. You can use adjust the pressure applied by hand and go only as deeply into the leather as needed. The curve allows for more agile precision with this task.