The armor is exactly the same as the shield, a defensive equipment that’s usually made from the same type of materials. And if it’s not, then it just means that its quality to block damage varies. But if the shield blocks general damage, wouldn’t it make more sense that armor does the same? You already have separate resistance types, including physical, so why can’t a build that has no shield be able to benefit from general damage reduction from the armor, since the armor and the shield are technically the same?