Also, although not strictly a debate around metric, the Fahrenheit scale gives you more granularity without going to decimals and requires less use of negative numbers on a day to day basis. And, if one is really concerned about a scientifically relevant temperature scale, we'd be using Kelvin, not Celsius.
My point is that if you want to use a "correct" scientific measurement on a day to day basis you'd use Kelvin. As soon as you're converting, you're converting whether from Celsius or Fahrenheit.
ADDED: There's an argument for Celsius vs. Fahrenheit of course in so far as the size of the degree is baked into some other SI measurements. But there's no particular other reason that Celsius is superior on a day to day basis other than familiarity for some. There's some logic to basing easy to remember numerical points around water properties but it's not clear that actually has a lot of advantages for day-to-day questions about how hot or how cold it is.
Can anyone provide any reason to use Fahrenheit scale, apart from historical ones? Legit question.
1. Fahrenheit is far more likely to cover the range of temperatures I encounter without having to use negative numbers. 0 is really cold. Anything below zero is really freaking cold. The temperature of the boiling point of water is mostly an academic point in my day to day life.
2. Fahrenheit provides about 2x the granularity of Celsius without having to use decimals
I'm not going to argue that if Fahrenheit didn't exist, we'd invent it. But it does have some advantages as an existing system.
ADDED: For engineering using SI units, of course Celsius and Kelvin make a lot more sense.