What is Emacs really? It's a virtual Lisp machine with a standard library for writing graphical text applications. It's more like the JVM than like Notepad.
It just happens to come bundled with a text editor (and a file manager, and a calculator, etc) as example applications. You're free to install a better text editor than the bundled example, and many people to (see the popularity of Evil, for example).
But of course, this is a much more complicated point in space to sit in, so Emacs markets itself primarily as a text editor and we get confusion like yours as a result.