Destroying a temple will destroy all of the associated houses.
If the defending city has invested a lot in Athena Houses, it is imperative that you prioritize Athena's Temple as it requires tremendous pressure or heavy burst to be demolished.
Defensive
As the enemy must destroy all of your temples to win, place the temple in a well-defended or hard-to-reach location.
Athena's power is particularly strong for all of the 8x8 buildings but much weaker for the 4x4 ones.
Athena's power is effective against crowd control oriented attackers, as it increases the durability of your troops.