Film camera 5000ISO has no noise. What concept?

Since ISO800, the noise has gradually increased. When reaching ISO5000, the noise of the image will magically drop to the same level as ISO800 due to the use of another set of processing circuits. Thereby having high sensitivity and no noise at the same time. Such excellent photosensitive ability surprised the audience. Why surprise? This makes it possible to shoot in low light. Documentaries and night scenes are simpler and more convenient to shoot, and the effect is better.