It shows that the LLM part found ways to mimic human conversation with a mechanism that is not the same as a typical biological brain. Then, you can push the AI system on adding things on top, but it is too late: these things on top will have no incentive to recreate from scratch the mechanism. The LLM pushed the system into a local minimum, and the rest of the system will not "go into a dis-optimising direction and restart from scratch".