
Here's one no-brainer case that should autoconvert (Farenheit to Celsius, note international region).
The use case is that I could simply highlight some text on a website, right-click -> search with kagi and get an understandable unit, no keyboard interaction needed.
Here's a short list of things I would suggest with an international (or any non-US region, vice versa with US):
miles to kilometers
miles per gallon to liters/100km
yards to meters
feet to meters
inches to cm
gallons to liters
pounds to kg
stones to kg
ounces to grams
fluid ounces to (milli|centi)liters
cups to deciliters
feet+inches (5'8" format) to cm
farenheit to celsius
dollars to euro (not sure about this one, maybe only converting to local currency on more specific region than international)
football fields to soccer fields 🙂
Let me know if you would like to contract me to compile a more comprehensive list.