If the items made by leatherworking gave a profit levelling leatherworking would be a no brainer, as it would be free or even better to turn all your own loot into leatherworking exp+councils.
In the current system there it will cost you councils to level it up. I am pretty sure this is intentional. The current system means getting high level leatherworking is something that is expensive, with the intent to be now that people who do this will craft gear for other players(this is how its good for the economy) - rather than every player crafting their own gear.