First of all, the °C is not the metric SI unit for temperature. K (Kelvin) is.
Second, even with Kelvin, nearly all temperatures that matter for normal human issues happen to be below 4000K, usually way below that mark. And with most of those temperatures, about all digits usually count. A core body temperature of 310K or 313K makes a BIG difference for the person involved.
First of all, the °C is not the metric SI unit for temperature. K (Kelvin) is.
Second, even with Kelvin, nearly all temperatures that matter for normal human issues happen to be below 4000K, usually way below that mark. And with most of those temperatures, about all digits usually count. A core body temperature of 310K or 313K makes a BIG difference for the person involved.
Celsius is the SI unit of temperature. Kelvin is the SI unit of thermodynamic temperature. They’re both defined in SI.
You can say anything with confidence and people will believe it
https://en.m.wikipedia.org/wiki/International_System_of_Units
Kelvin is the base unit. Celsius is a derived unit, just like Watt or Newton. But they’re all SI.