Development 4
Of course, that was just one aspect to it. There were a lot more benefits to having Spiritual Energy around, as it was more directly beneficial to living species, nourishing their bodies and genetics from birth.
Worldly Energy unfortunately did not do as much. It was certainly easier to absorb and use, and also did most of what Spiritual Energy did, bit it was not as proactive.
Worldly Energy was more for inanimate objects and the planet itself to benefit from rather than the living beings, while Spiritual Energy was the opposite. Of course, both could do the work of the other, but not as good.
For example, Spiritual Energy could nourish inanimate objects with special characteristics and create Heavenly Treasures, or enough Spiritual Energy could be gathered to create a Spirit Stone, or Spirit Stone mine.