The development of the universe had been all about the planets, stars and star systems, constellations, and such.
It could be said that all the celestial bodies had been refined to the utmost in the previous systems, growing to a complete system.
All heavenly bodies after the seven planes were created from this perfected and complete data.
The Eight Directions mainly focused on meaning and causality.
Each of the eight directions had a purpose and they could affect each other.
The North was generally associated with ice and cold. Mountains and rockery.
It was also a starting point, the North Star.
Those with powerful cultivation but who had no interest in mortal affairs would often go North as there were few beings there.
The South was associated with farming and mortality.
It was also where all things evil were thought to gather, as it was a good place to hide.