Even though the process was dangerous the benefits were true immortality. The immortal cultivators would no longer be forced to rely on their physical bodies to survive.
They would be capable of restoring their bodies to their prime and maintaining it forever while still keeping their brains sharp. Not only that even if their heads were blown off their shoulders they could survive as long as their crystal brain was intact.
So once the crystal brain was fully formed and synced with the user's original brain they were presented with a choice. They could follow the path that the Immortal Welse followed and actively remove their crystal brain, skull, and spine from their body.
This would allow them to not have to worry about what happened to their body at all. Even if every single one of their atoms were torn apart they could always come back.
