Therefore, most powerful beings nearing the end of their lifespan will pursue the legendary reincarnation rather than body seizing.
Unless it's someone who unexpectedly faces adversity, but originally had a long life span left, for whom body seizing, with the spirit origin still intact, can rapidly restore their original strength, offering the greatest benefits.
Both body seizing and reincarnation require an extremely strong spiritual body to succeed.
Reincarnation, in particular, demands one to gain rebirth while retaining memories, which is exceedingly difficult.
The Reincarnation Saint Emperor wishes to reincarnate and retrace the path of cultivation, hence the "Reincarnation Scripture" in its later stages mostly modifies methods concerning the continuation of the spiritual body.
There is even an entire chapter dedicated to this subject.
"True Spirit Method... The Reincarnation Saint Emperor's research has reached a profound level!"