No one forbids taking Kifre and developing diplomacy. If troops join for free, the best use is to send them to the pit, unless there is an urgent need for troops. That's basically all there is to it. The Temple of the Elements definitely loses out compared to the Necropolis and is inferior to the Orcish one, but it's still not useless.
Taking diplomacy for Kifre means giving up the speed aura for less than 10 Fury and about 15 Aces. No thanks.
In my opinion, it's an absolutely useless building.
Творят настолько черные дела,
Что до таких блистательных идей
Не вдруг дойдет и записной Злодей
Темный адепт клана GODS