You’re correct. In a lab setting, 0C and 100C are not arbitrary.

In the weather forecast, they are.

Which ties into your final point, it’s hard to define a scale that is best for everything, which is exactly what I’ve been saying this whole time. Fahrenheit is better for some things, Celsius for others.

The only reason people in this thread are saying otherwise is because for some reason they’ve tied up some significant part of their self-worth into their belief that “lmao DAE fahrenheit bad amirite??1?”, and they mistakenly believe that those of us that understand nuance are trying to belittle or disparage them in some way. I assure you, we are not.