This mattered little (if at all) in CI 2, and you are linking to the CI 2 documentation.
It also doesn't matter on Windows, which I assume you're testing examples on, because its underlying file-system is not case-sensitive.
When you actually deploy your application, it will likely run on a UNIX-based OS, and it does matter there. Especially with CI 3, which requires Ucfirst naming for anything that is a class.
