Don't get me started on Fahrenheit! What is room temperature in the US? Don't give me any wild numbers above 50!
Why do we need Fahrenheit?!?
Because the calibration is finer, so you can understand the actual temperature better. I mean WTF 30 should not be that much hotter than 20, that's just wrong. There need to be more gradations in between. Also because "below zero" should mean "seriously effing cold," not just "cold enough for water to freeze."
I think the gradations in between are "21," "22," "23," etc. ;)
There's an infinite amount of gradations in between with decimals.
The problem isn't the gradations, but being familiar with what they mean.
For example, I could start a temperature system where 0.32 is where water freezes and 2.12 is where it boils. There's not a ton of gradation in whole numbers between 2.12 and 0.32... yet you can instantly understand what temperatures are comfortable (for example, it's a pleasant 0.75 where I am right now).
Once you're familiar with a system it's not a problem.
I mean, why have a 0-100 gradation? Why not 0-1000? That will allow even more gradation and precision.
It's just getting familiar with whatever the system is.