Leather finishing tools are used primarily to refine the edges of leather work. When cut, the natural fibers inside leather are exposed. They might show as loose or “hairy” as the fibers stick out. This is generally unpleasing to the eye, and also exposes the leather to faster wear and damage from moisture.
Finishing the edges helps to smoothen and seal the fibers. This makes the edges stronger, protects the leather, and is more visually appealing. Leather can be finished using a combination of abrasion/friction and waxes/sealers. For my detailed article on finishing tools, click here.