What is a formmater used for?
The main purpose of formatters is to beautify data for better legibility and for debugging purposes. For example, if you are a programmer, you will deal with minified JSON files, compressed XML documents, CSS files or with HTML code.
Because of performance reasons (for example, reduce the file size to reduce network traffic and increase loading speed), data will be output with no line breaks and with very few white spaces, becoming extremely difficult to read or edit.
Thus, if you try to edit or debug minified data, it will become an almost imposible task. For this reason formatters exist.