SI unit of temperature is known as the Kelvin unit and it is basically used in physical science to measure the temperature. In the practical world, we use the Fahrenheit to measure the temperature in the western countries, and the Celsius in the rest of the portion of the world.
It is just the other measure of measuring the temperature which is only used in the scientific field to measure the temperature of different things there. In other words, Kelvin is used to conveying the temperature using the other medium, then the Fahrenheit and the Celsius.
It is just like if a person wants to express or measure his/her height in the meters rather than the feet, inches or the Centimeters. 0 Kelvin is known as absolute zero and in the measurement, the fraction of 1/273.16 of the thermodynamic temperature is considered to be equal to one Kelvin