Thermocouple vs Thermostat

Question

Why don't modern engines use a thermocouple (electronic temperature sensor) instead of a (wax element) thermostat?

Answer 1

A thermocouple merely generates voltage according to the temperature, while an automotive thermostat is basically an autonomous temperature sensitive coolant valve. You can't replace a thermostat with a thermocouple because their functions are completely different. You could replace a coolant sensor with a thermocouple, but resistive sensors are more convenient to use in this case.