For mortals, faith energy is something useless because of the obvious reason that faith energy does not affect them whatsoever. However, for any divine beings, faith energy is more important compared to physical territory.
If any divine beings have the ambition to widen their physical territory, their main intent is usually to gather as much faith energy as possible.
After they conquer the land, they can farm the faith energy of the beings living there. Fear and reverence can be included as forms of faith energy, but they are weak. The strongest faith energy still comes from those who worship them sincerely, their believers as a god.
Divine beings will spread their faith across the land to raise the number of their believers and strengthen themselves. But physical territory is not something that is absolutely required to gather faith energy. Even someone outside their territory who holds faith in a god will still provide faith energy, making that god stronger.
