Why would an app be a requirement for a search engine? To me it would make more sense to be aligned with how many users the search engine has. 5,000 unique per month, or whatever.
I have the Kagi app on my iPhone, but just so it can be an extension in Safari. In a perfect world, I would be able to go into the settings, add a custom search engine, and be done with it. No app or extension needed. Then when it hits a threshold it can be added as an easy option for people to pick from a list.
> Why would an app be a requirement for a search engine?
Because otherwise you can’t use it as a default search engine on the platform, because it doesn’t allow it. Same for iOS. They had to write an app to intercept search requests and redirect to Kagi.