The point of CUL is to make money and lots of it, it's probably the highest profit craft. Sure the best items you can make might only make 2k profit or so but you can sell them in stacks of 5/10 and they sell really fast. Cooking isn't about making tha one item that makes you rich, it's about churning out volume to make money. It will also save you a ton of gil when you start using food yourself.