Filling out form information is one of the core principles of writing tests with Selenium. The test will need to register a new user, or make a purchase, or log in to an account at some point. The default values pattern aims to extract any data that our test does not actually care about. Tests should not have to know what the username and password are for every test user on every environment we have. Instead, it should rely on defaults that are appropriate for the current state.
Isolating irrelevant data from the test implementation has many advantages: