Although he lost his body, he gained a lifespan nearly as immense as that of the Immortal One!
It sounds pretty great, and he did indeed live longer, sparking a craze amongst his contemporaries to seek out such little worlds, but...
As a BeastMaster, his decision to abandon his Pet Beasts inevitably led to the loss of spiritual balance in his Spiritual Puzzle, which triggered a terrifying mutation, contaminating the entire small world and causing a great upheaval.
The final result was...
That giant and the small world were severed from the main world, forming a wandering forbidden zone of life in the Void!
Did it further mutate now?
Or has it already been destroyed?
Given this cautionary tale, unless absolutely necessary, the top powerhouses would rather research life-prolonging elixirs than risking mutation.
Just like accepting a gift from the Evil God, after mutation, it's uncertain whether one can maintain self-awareness—it's no different than being dead.