What’s the greater significance of the immortal fluid, Amrita?

Arguably the most heartbreaking scene in a film filled with heartbreaking scenes is the capture and poaching of one of the Tulkun, the whale-like creatures who have a symbiotic relationship with the Metkayina. We also find out that the poachers don’t even harvest the full creature, they just suck out a substance called Amrita which is said to stop the human aging process. As a result, it’s the most valuable resource on all of Pandora with a single vial being worth around $80 million. (Which, in the future, is that even a lot anymore? We’re meant to think it is though.)
If you’re James Cameron, you don’t mention a substance that grants humans eternal life for no reason. It’s certainly going to come back and play a huge role moving ahead. But is that to keep characters like Edie Falco’s General Frances Ardmore alive? Someone else on Earth? We don’t know.