It is named after the British physicist, Lord Kelvin, after his work on thermodynamics. A Kelvin is the basic unit of temperature based on the absolutes scale and is the standard unit for measuring temperature.

Generally the degree Kelvin is considered the fundamental interval on the thermodynamic temperature scale.

Because the Kelvin scale is an absolute scale.

In the context of thermodynamics, 2 K is twice as "hot" as 1 K. And 3 K is three times as "hot". That is not true of the Celsius or Fahrenheit (or other temperature) scales.

Celsius and Kelvin scale are also valid and useful.

Celsius scale is a conventional scale based on the freezing and boiling point of water.

Kelvin scale is an absolute, scientific, based on thermodynamics scale.

The Kelvin temperature scale