It is very useful to know that you can cook a chicken in a sauna. Checkmate.

But seriously it is because it is easier to just use international standard for everything.

Imagine the carnage of every single country having their own definition of a mile. (Every single country has their own definition, but that pain is (almost) gone thanks to km.)

There are just 8 different temperature systems on Wikipedia.

https://en.m.wikipedia.org/wiki/Conversion_of_scales_of_temperature __ Why does it need to be more complicated than necessary?