Why is a Cloak of Protection only uncommon? A Cloak of Protection and a Ring of Protection are mechanically the same item. Both provide a +1 to AC and all saving throws. This is quite powerful in my experience, as literally every character I have had at my table who has the opportunity to get the cloak does, and because it's uncommon it's not too hard to find or make. Yet the ring of protection is a Rare item (if memory serves correctly).

Why is it then, that the Cloak has the same worth as a cap of Water Breathing or some potions?