For the Heavenly Court, their expansion entailed integrating everything under their governance, as mere violent conquests and demolitions hardly yielded substantial benefits. Instead, civilizational means of incorporating these elements proved most beneficial in maximizing gains.
Similarly, it was precisely because of such methods by the Heavenly Court that most worlds lacked the resolve to fight to the death, risking mutual destruction.
After all, for them, these outsiders did not adopt an attitude of violent oppression and conquest; rather, they brought different civilizations, especially for worlds originally confined by their own Realms and unable to advance further.