Even after successfully breaking through to the Foundation Establishment Realm, one still needs various methods to enhance one's strength, to avoid being killed by others.
Even someone like He Song, a Golden Elixir Master, would use various methods to strengthen himself.
As for the purpose of becoming stronger, it is naturally to make oneself safer.
And moreover,
even after successfully breaking through to the Nascent Soul Realm,
as long as one is in the Cultivation World, one still needs to continually strengthen oneself to avoid threats to one's life.
In such a situation, it was natural for He Song to feel that three puppets were not enough.
He needed more Gold Core Puppets to become even stronger.
Only then could he properly survive in the Cultivation World.
Of course, since he already possessed three Gold Core Puppets, He Song himself was also quite powerful.
