They chuckled at that. It is expensive, but they are of one mind in that the avatar divine spell is useful. Their main bodies will still be in the divine realm when using it. It is only a spiritual form created with 100 divine energy that gets to act on their behalf in the mortal realm. Because of this, they act both in the divine and mortal realm.
The first major disadvantage is that their divine bodies can't move when they are using the avatar spell. The second disadvantage is that the avatar can't be created anywhere. They can only be created at altars built and consecrated in their names.
The third major disadvantage is the need to maintain it with divine energy. Every second of it will cost them divine energy. All of these are further worsened by the fact that the avatar doesn't have divinity, so it can't interact physically with the mortal realm. They only use Authority and divine spells through it.