> Genuinely, why would they leave any data on the table if they don't have to? That's the entire purpose of the browser.

Because extracting and using that data may not be trivial, practically and legally speaking.

I am sure they use the chat input you send them for training. But to say that they transfer all the websites you visit to their servers, or that they can monitor your keyboard input either by continuously streaming your window or your keyboard events to their servers. All of that would be a small technical feat and noticeable in the created traffic.

My belief is that they simply hacked together an AI web-browser in the least amount of time with the least amount of effort, so that they can showcase another use for AI.

That would be a much simpler explanation than them building a personal surveillance tool that wants to know what you've typed and keeps track of the time you've spent looking for shoes.