You are already using Celsius as well. If you just did not know Fahrenheit, you obviously would not miss it. To us Celcius feels just as natural as Fahrenheit does to you. It would be nice to have one global system we can agree on, just like we agree on english being the language of the internet. English is my 2nd language and if I can learn a whole other language, then americans can learn metric. (Is celcius part of the metric system? I have no idea tbh)