My feature suggestion is for Kagi to make an official Translate extension (plugin) for use with Apple's Mail.app, which comes pre-installed on Mac computers, and is used by millions and millions of people.
Such a feature could be the single most important and helpful implementation of machine translations, helping people understand messages they receive, and write messages and replies in their own language and send a translated mail.
If we strip away all our notions and preconceived ideas of computers and the Internet, and ask ourselves what would be the best way to use this technology, then writing and reading messages in any language would be on the top of the list.
There are currently no translation extensions available for Mac Mail.
GMail has translation - only for messages received - and it doesn't function well.
DeepL offers translation integration for Outlook.
The Mailspring app offers translation built in.