Error on login page

Consider two scenarios:
1- On the login page, when the user leaves the Email field blank and clicks on the “Log In” button, they will get the error :“Invalid Email or password.”.
2- On the login page, when the user enters an invalid email address like test and clicks on the “Log In” button, they will get a browser tooltip error.
Why the second scenario has been handled with browser tooltip error? It could have been handled via throwing the same error that the user gets in the first scenario.
URL: Exercism