Did you know that #KDE 's KRunner accessible via Alt+F2 hotkey(combination) can do simple math, convert units and currencies for you?
All of that offline. No need to query a web search engine or use a web browser at all, not to mention asking a large language model that'd probably give you wrong results at a million times higher computational, memory and energy cost than what this launcher does.
I love you, @kde ! Plasma is the best :D

Sorry, no caption provided by author

Sorry, no caption provided by author

Sorry, no caption provided by author

KDE's handy launcher answering a query:
260 km/h to mph
---
161.557 miles per hour (mph)