Spells/skills only benefit from ‘Attack Damage Converted to Health’ if they scale with your weapon damage. Thanks to the Conduit of Divine Whispers adding 24% weapon damage to AAR, this amulet lets you life steal with AAR. So yes, with amulet = % ADCTH works. Without it’s a worthless stat.
Bat is a proc and its own damage source so it will always steal life even if bound to a spell without weapon % damage.
But since the two amulets (Conduit and Mythical Essence of GD) can be hard to get, this leaves Pulsing Shard as the only option of life stealing with AAR whilst lvling/grinding gear.
Also both the Mythical Essence and Pulsing Shard work differently as they add life steal directly to AAR, this bonus can not be increased with the ADCTH stat