I think some of this gear is meant for those who value fashion or looking unique over having over the top stats. It works like this:

Look like everyone else: Crafted Gear with materia to have amazing stats.
Look unique from everyone else: Dungeon-dropped equipment that's commonly mediocre to crafted. Some exceptions.
Look semi-unique, but mostly like everyone else for free: JSE artifact armor that's commonly not much better than dungeon loot, but looks sweet. Since it's pretty much free anyone who wants to wear only this type of gear can get it. Again, some exceptions to the rules but are commonly outclassed by craftable gear fitted with materia.