If ixali give T4 materia it would way to easy to gear up and meld...
Plus actually WE have alot of way to have crafting materia
Either spiritbond lv50 patrician stuff or higher level
Or killing ourself spiritbonding new i170 ring and maybe get a T5 materia

Anyway spiritbonding crafting stuff is'easier than battle one (since you can have only 3 materia instead of 10+ on battle classe)