In my opinion the best DRK relic piece next to Abyss Cape. Coming from an Elvaan the INT+8 is very useful for DRK's INT and STR-based weapon skills such as Spiral Hell, Insurgency, and Ground Strike. These are also a great piece for dark magic, even better if you have the resources to HQ them. If Crimson/Blood Gauntlets are not in your grasp you may want to pick these up :D
any magic you cast this should be macrod in. as for the +DEX im just guessing its so hit rate doesn't drop when you swing after a spell and you didn't gear swap back to TP gear in time.