Just because you manage to deal with C doesn't make it better.
Do you see the parallels? You tell Americans all the benefits of metric, they don't care. You tell Europeans all the benefits of Fahrenheit, they don't care.
People don't want to change.
> It keeps the numbers smaller.
No, it doesn't. You need 3 digits since you need the decimal (-20.5).
You only need decimals for highly accurate measurements, but at that point you'd need decimals for Farenheit as well.
> You tell Europeans
Erm, how about the rest of the world?
Decimals are only for those who are making a fuss over nothing unless they're doing something that requires precision, like chemistry or in rare cases cooking.
There's no benefits to Fahrenheit. If you want to argue they're both arbitrary, fine, but the entire world uses °C, so get with the program.
I could get on board with kilometers, if I had to, because the conversion factor is simple enough to do in your head (roughly 3/5), but trying to figure out what anything is in Celsius is just a little too complicated.
Why let's just change the numeral base to 5, or use roman numerals for that matter. Then scientists can finally stop to convert some arcane unit to get to the Standard International Base Unit, ie. Kelvin. At least everyone gets to convert their numbers then and it's only a division by two, too.
</rant>