Hm, yes and no, I mean it is also dependant on the items specifics.
Even if they are more than one effect, in most cas it is one major, the others lessers/secondary.
Example with the mentioned Rainbow Ring : +15 beauty, +5 Happyness. The girls used it as to happiness, the same they used mana crystal for mana (that item being among the few who have quite a direct use since single effect).
This said, a job of some interest could be "buyer", who based on a player set list, will seek to find sources for specifics items (thinking as to wholesale setting).
This getting in the way of the current crafter jobs, just setting them (or using others professional) as to obtain specifics (That said, the way it is now, a Jeweler who kept for 12 turns crafting bauble necklace..) items.
This said, since the magic stat is quite secondary as it is, it could be of use as to the enchanted (not basic) effects of the items, either trough an "enchanter" plain job, or simply by assigning a set requirement (as a recipe) for the chosen item. Guess it involve some code view as this.