The intentions are good, but yeah, it seems like an half-baked solution. Why not integrate this tool directly into the browser UI? User goes to whatever websit

The intentions are good, but yeah, it seems like an half-baked solution. Why not integrate this tool directly into the browser UI? User goes to whatever website, input his login creds, Firefox reads the login email and sees if the email+url combo is in the HIBP database. If yes, a message will advise the user to change his password. End of story.