The Page editor is a simple page manager that enables you to create your page's content, its publishing options, settings, overrides, etc.
The default page editor provides several input fields, which also can be extended with custom fields by modules.
Writing content for the web with WYSIWYG editors is relatively easy, but they usually result in terrible code. Markdown is a simple way to format text that looks great on any device. It doesn't do anything fancy like change the font size or color. Markdown is simple to learn and produces valid HTML output.
Scriptor comes with built-in support for Markdown. But it is also possible to use plain HTML or even write a custom Pages module that allows you to use a WYSIWYG editor.