Improved Devotion Aura/Redoubt, just a question

It is a commonly accepted axiom that this tier 1 Prot talent (Imp Devo Aura) is horrible and absolute must-not-take.
I agree it is pretty weak. At 5/5 and max rank Devo aura, you get a grand addition of... 183 armor (my own numbers, decimals skipped). While I suppose it could mean something for clothies, this is a couple of decimal points in damage reduction percentage for plate users at best.
Tanking with a Paladin, preferring Redoubt over this is a pretty easy choice. Redoubt gives you +30% block chance if you just press your X key, and coupled with the Shield Spec it makes for decent mitigation (likely good threat as well if compounded with BoSanc).
However, I've seen a fair deal of retribution and deep holy/healing builds that also pick Redoubt over Improved Devotion Auras, even if they do not use shields at all (some of the paladin healers use regular off-hands like the AV exalted +healing item), as a path to get Precision or BoK/Guardians' Favour respectively, even if Shield Spec isn't picked.
My obvious question here is, why? Redoubt does literally nothing in this case.
For deep Holy/healer paladins, those wearing pure +healing cloth and leather and a non-shield offhand, the Improved Devotion Aura at least adds something (even if really minor) to the tank they're teaming with if he's about to face a heavy hitter mob, or maybe to protect oneself if getting attacked as a way to compensate for the squishyness resulting from wearing such gear. Redoubt just does nothing for you nor anyone in the team.
While retribution paladins will probably be using Sanctity Aura most of the time, I suppose there will be off moments when in order to counter damage spikes, you can swap to Devotion Aura for a 915 or so armor increase. The only thing Redoubt does for you is allow for a reck charge counter, which is something that doesn't even count for non-reckoning retribution paladins.
Is this preference a thing because paladins should keep a shield in their bags for defense, and you swap to it when getting attacked, thus profitting of the Redoubt proc? I am not seeing any other reason.
I agree it is pretty weak. At 5/5 and max rank Devo aura, you get a grand addition of... 183 armor (my own numbers, decimals skipped). While I suppose it could mean something for clothies, this is a couple of decimal points in damage reduction percentage for plate users at best.
Tanking with a Paladin, preferring Redoubt over this is a pretty easy choice. Redoubt gives you +30% block chance if you just press your X key, and coupled with the Shield Spec it makes for decent mitigation (likely good threat as well if compounded with BoSanc).
However, I've seen a fair deal of retribution and deep holy/healing builds that also pick Redoubt over Improved Devotion Auras, even if they do not use shields at all (some of the paladin healers use regular off-hands like the AV exalted +healing item), as a path to get Precision or BoK/Guardians' Favour respectively, even if Shield Spec isn't picked.
My obvious question here is, why? Redoubt does literally nothing in this case.
For deep Holy/healer paladins, those wearing pure +healing cloth and leather and a non-shield offhand, the Improved Devotion Aura at least adds something (even if really minor) to the tank they're teaming with if he's about to face a heavy hitter mob, or maybe to protect oneself if getting attacked as a way to compensate for the squishyness resulting from wearing such gear. Redoubt just does nothing for you nor anyone in the team.
While retribution paladins will probably be using Sanctity Aura most of the time, I suppose there will be off moments when in order to counter damage spikes, you can swap to Devotion Aura for a 915 or so armor increase. The only thing Redoubt does for you is allow for a reck charge counter, which is something that doesn't even count for non-reckoning retribution paladins.
Is this preference a thing because paladins should keep a shield in their bags for defense, and you swap to it when getting attacked, thus profitting of the Redoubt proc? I am not seeing any other reason.