It guarantees that the color will look on a product just like you selected it. In Germany we have an older system called RAL, which is sufficient for most use cases. For example if you ordered a window in RAL 7043 and need to repaint it, you can go to your next hardware store, oder some paint with that color code from any manufacturer, and colors will/should match. But the RAL system applies more or less only to the physical world.