About Darkblaze Garb 's contradicting dmg conversions

As title, it seems like a chaos dmg sets. However, its necklace has vit > fire while helm gets fire > chaos.
What’s the point???

As I see it, it’s like this: The set does boost fire damage (albeit for an unimportant amount). The only vitality damage you would be doing would come from Second Rite, and if it was converted to chaos, you would miss out on vitality decay converted to anything. I think the point is to get burn damage.