HoneydewSovereign There is a good theory in a novel that i was reading. Not a fact, but a theory...
It's said that beasts take 1000 to 3000 years to gather enough 'pure' heavenly energy naturally to finally form their human form when they reach perfect balance. This happens not as a 'conscious decision' but one taken by instincts. And thus, they form their human bodies from the pure heavenly energy and become Divinities(basically immortals). At the moment of their human body forming is the first and the last time they can manipulate the 'pure' heavenly energy in their lifetime. Like a cosmic joke played on them, the pure heavenly energy is forever barred from them at that moment. It seems like a joke as they can no longer gather pure heavenly energy as complex thoughts and emotions of a human body prevents them from ever reaching 'perfect balance' again, but it is also said that only with complex thoughts and emotions that a human body has can they ever hope to reach the next level of ascension. Without it, they can't take the next step. It is sure that Qi is inferior to the 'pure' heavenly energy in every way possible. It is like a part taken from the pure heavenly energy in the air, but not the whole. It is not known whether a Divinity ever took the next step, so who knows if it's actually a disadvantage or not for them to form human bodies with complex thoughts and emotions?
It is a good theory from the novel that i'm reading. It doesn't really tell you every information about the world with a godly narrator, so i can only know what the mc of the novel knows so far.