Now that Nirn will only apply to the Spell Resistance on the item it is on and not your total Spell Resistance is Nirn going to be useful at all on armor?

Am I viewing this incorrectly? I thought the armor value of any piece of gear equals both spell and physical resistance granted by that piece. Since Reinforced increases the armor value doesn't it already increase the spell resistance on a piece of armor? If I'm wrong please let me know.

If I am right maybe nirn values will be higher than Reinforced to make up for this?