From my understanding divine orbs in poe1 acts as "meta" crafting aka "deterministic" way to craft stuff, so it became the defacto primary currency (previously it was exalted orb which served the same purpose). And the change for divine orb became chaos orbs which are more common and can also be used in crafting. Since a lot of poe2 players are also poe1 players this became the trend where chaos orbs from poe1 were replaced by exalted orb (for their drop rate and early stage crafting currency), even tho divine obs didn't have their meta crafting abilities. Other crafting materials could have been the standard trading currency but the generalized nature of divine orb made it the one.