i only leveled craftin for these reason

1. making my own gear to spiritbind when farmin materia its a million times cheaper lol
2. being able to melp materia myself sometimes its a hassle finding some1 to do it for ya
3. making my own furniture for my house some furniture is insanely expensive

but crafting isnt really needed u dont miss out on anything if dont wanna level crafters but its 1 of the better ways to make fast gil