It would be useful if you live in the United States, or any of the dozens of countries that use the system either as a standalone measurement of temperature or as part of a dual system. The British Virgin Islands, Antigua, Barbuda, the Bahamas... Etc.

I find it actually kind of a fun way to start a conversation with anyone outside of the U.S. by attempting to convert my local weather to Celsius. I'm on international calls fairly regularly and (can't blame anyone for this) telling anyone outside the US or the countries above the temperature in fahrenheit is like speaking a foreign language.

Oh, in case you're not aware, generally a feature list isn't specifically catered to one specific person.

Fun to fuck with people in winter that it will be in the thirties tomorrow. I like to show little kids and see what they say. If they’re younger than ~8, it tends to work, then I get to tell them about the world a little more and if they’re interested, teach them how to convert. That was the first conversion I figured out, it’s pretty easy, and it’s applicable to the real world, so it’s great at getting kids into math.