In reply to David Anderson.

why would someone want to do this?

The primary reason for this would be to enhance your shortcode so that it is more visual based with gutenberg, so for example rather than n instagram shortcode, the new editor (gberg) would render the instagram feed with limited functionality in the editor so the user can see how it will look and flow with their content, visually.

As a developer there isnt a whole lot of work to make your current shortcode gberg ready - thats the whole point of this article.

For some people shortcodes are still really tricky. Most of my clients cant grok shortcodes as they are.