Leatherworking as a profession is in some ways quite similar to Tailoring. Just like tailoring, leatherworking allows one to craft different kinds of equipment/gear to boost certain stats of a character. While tailoring mainly focuses on different types of cloth that is dropped

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from monsters in World of Warcraft, leatherworking depends heavily on leather which can be scavenged/skinned from beasts in the world.
Besides being able to craft different kinds of gear for yourselves and others (to make some side cash), leatherworking does have some additional goodies. To name a few, leg armor patches, different kinds of drums that boost certain type of stats for a stipulated amount of time, quivers and ammo pouches that can be used by hunters, Mining and Inscription bags used by Miners and Jewelcrafters to store ores and jewels etc.. etc..
And last but not the least are the leatherworker-only patches, also known as Fur Lining which was introduced in Wrath of the Lich King patch. These patches are incredibly useful as they boost a certain types of stats of your choice, which can be applied to your bracers. Of course this would negate the ability to have a normal enchant on that particular slot but these leatherworking-only enchants/patches are far more superior to normal enchants that Enchanters can normally do. This is quite similar to Inscription specific shoulder enchants or Jewelcrafting specific gems or Tailoring specific cloak - embroidery or Engineering specific hand mounted pyro rockets.