When Sha Chen saw that Golden Core, his eyes widened. This was the Golden Core of a Daluo Golden Immortal. Even if most of the Divine Power resided within Jinmaohou's Primordial Spirit, the Divine Power contained within this Golden Core was probably even more than what the Tongtian Hierarch had gifted him last time.
Jackpot.
Ordinary monsters are not easily plundered of their inner cores; if they die, they use their Primordial Spirit to envelop the core and flee. They basically refine the inner core and Primordial Spirit together, sharing both glory and loss. In reality, when it truly comes to escaping with the Primordial Spirit, they would not let someone take their inner core. That would be akin to erasing hundreds of thousands of years of hard cultivation and also losing the chance for reincarnation.
Therefore, when monsters fight, even if defeated, it is rare for their inner core to be plundered. At most, the Primordial Spirit is captured along with it.
