Somehow this still isn't implemented, and there isn't an open feature request for it?
https://kagifeedback.org/d/2031-currency-conversion-ie-100-usd-to-sek-should-display-widget/30
This was closed as "done" but it's not. There is no widget for currency conversion. It just displays a Wolfram Alpha answer with no ability to type a different amount, convert back from the other currency or select a different currency. The conversion rates are often just wrong.
There should be a widget similar to the one on Google, Yandex, DuckDuckGo or any other search engine.
Every single search engine except for Kagi has a proper currency conversion widget. It's crazy that people who use an ad-ridden search engine can convert between different currencies and yet users of a "premium search engine" have to use xe.com or some other random website to achieve such a simple task.