I'm trying to decide if I should require attunement for an item. A Paladin in my group recently obtained a holy sword (that he attuned to). During that process, his hand and forearm were transformed into a living gemlike material and which now provides certain bonuses and abilities (+2 to Strength for uses involving just the hand; once per day, a hit that would take him to 0 HP will take him to 1; and 3x/day if an ally within 30' takes a critical hit, it becomes just a normal hit). So, it's powerful in its own right...but there's no way anyone but the Paladin will be able to use it. So, is Attunement really necessary?