“A pint’s a pound the world around” is the ditty. Wherever do you think the metric system got the idea for 1l = 1kg? The serial numbers just got filed off that idea and claimed it as if they invented it. If you look closely, there is a shocking number of base ideas of the, “common” usage measurement system, were simply copied and just re scaled and give new names. Since the base values differ, Celsius and kelvin ain’t the same. Not that it matters of everyday usage. I just want to know if it’s going to be cold, nice or hot when I get up in the morning. I don’t worry about what scale I’m using.
It’s pretty amazing when you start really looking at things to understand just where something originated from, it becomes apparent that there is very little new under the sun.