Camera and floating point origin

I have this video about it. I find his tutorials very good. That’s exactly what it’s about. But what I don’t understand is why it’s a floating point origin when the camera still has large coordinate values

here is the codelink

His World consists of many chunks. He talks about putting the origin in the camera and instead performing the movement on the objects in the opposite direction. I understand the theory. But I am not yet aware why the camera in his code than still has large values and the camera then moves. There’s something I haven’t understood yet, because what he does it has an effect.
This is a very interesting topic. So far I have had little to do with changing the reference system. That will probably keep me busy for a while