I have cooking at 100 purely for my self and my friends.
If I could take a 2nd craft to 100 I would take up alchemy or woodworking for the same resion.

While I do craft to make gil some times.
Most of my income are from farming rather than crafting.

I use my crafting skills for my linkshell, friends and my self.
So in this since I craft to become self sustaining.