Actually, what has been discussed is that the displayed oil temperature is calculated or derived from conditions and a (proprietary?) set of data that is collected by other sensors. The is no actual oil thermometer used to determine the oil temperature. My personal experience is that the displayed oil temperature (in the AMG menu) is within a degree or two of actual temperature measured using an infrared thermometer. With regard to coolant temperature, the display value in the AMG menu is inconsistent with the value you can read using a scan tool, often 10 degrees or more.
So, we have a derived oil temperature that is more accurately displayed than a measured coolant temperature.
I didn't watch the entire video after Tasos installed the new coolant sensor. Was there more to it?