The body is the earthly vehicle for using the power of the soul through consciousness.
Its nature is more than anything Its nature is more than anything spiritual Called spirit by the Yadratians,
and more importantly, Goku could use the genkidama in the other world (Y'know, the place of disembodied souls) and detect spirits.
We know that souls maintain their consciousness in the afterlife and their ki, as mentioned before, Raditz fought with Yenma.
A person's body also retains that person's power, just as consciousness has, since they were linked to the soul.
In Buu they awakened the consciousness of the great lord of Lords, but his ki was in uub Bulma scenes before mentioned that mortal ki was not enough, but uub despite also being mortal, had divine ki inherently
Buu became stronger and Goku mentions it, but at no point does he say that his ki changed. Why? They awakened his consciousness, but the soul wasn't in that Buu.
And the conscience of the Lord of Lords, knows his techniques, but he did not have the power to do them. Moro says he does not have the same power as back then.
That is, the body adapts and preserves the
power of the Spirit, consciousness, your personality, potential and part of your essence, and your soul, your essence and your ki, for those reasons Black was still a god despite being in a mortal body, both his consciousness and ki migrated to Goku's body, and that's why Uub is a mortal with divine ki.