I'm presuming the best of the best gear is obtained through raids and such, and considering how my combat levels are far outweighing my crafting classes, is it worth to go and level them up? I know you need level 20/19 to add materia to equipment, but is there any reason to get higher?

Any and all reasons are appreciated, I like the crafting classes, but I really don't see much purpose to making so much useless gear when I could be spending time getting closer to endgame raids and such ://