Botanist will greatly benefit Culinarian. No DoL will benefit leather worker if you don't train other DoH jobs (Armorer, Goldsmith and Weaver in particular).

In any case, you will have to spend a lot of money on materials if you train just a single DoH and a single DoL. Doing leves might help you break even though. Some DoH are better in terms of costs and benefits from DoL, for which Leather Worker is one of the worse.