Hmm, if it spiritbind and convert the normal way to materia, I would be OK with that I guess. Same for Darklight and Myth and Coil gear, why not. Why should worse stat, easier to obtain crafted gear convert to good materia and these items not?

Wouldn't want to simply trade primal weapons for materia without spiritbinding though. It's too easy to do the primals for that.