[Shovah32]

Prophets get the bless because they are automatically blessed at all times. Apart from them and commanders with shrouds of the battle saint(S1 and 5 pearls but takes up the body slot) only sacred units which are blessed in battle can gain the effects of your blessing.

Shrouds of the battle saint can be very useful on mages or valuable commanders:
A bless like twist fate is great protection from remote spells, even N4 stops mages losing health from afflictions, a death bless means remote attack spells can cripple enemy armies and minor astral gives the ever-useful magic-resistace boosts.

Also, your god benefitting from your bless would be insanely powerful for example an E9 cyclops has 29 protection. Add some reasonable armour and an E9 bless to that+the reinvigoration from the bless and summon earthpower+nature bless regeneration and you have an almost unkillable early game SC with a powerful bless(good for sacreds like Lankas and Niefelheims).

He would have insane protection(29+1 from summon earthpower+more from E9 bless and armour), huge regeneration(high health+Nature bless), 8 reinvigoration(4 bless+4 summon earthpower, can add more with items) and E10 to cast spells like bladewind.

Mages(including pretenders) already gain the previously mentioned passive benefits from their magic, adding the bless to a god would just be a bit too much.