How is this plugin related to ckeditor5-react and ckeditor5-build-classic?

[ansmlc]

Strapi blog has a guide on adding CKEditor:
https://strapi.io/blog/how-to-change-the-wysiwyg-in-strapi

But it doesn't use this plugin. It adds:
yarn add @ckeditor/ckeditor5-react @ckeditor/ckeditor5-build-classic

Is this plugin an alternative to the above? What is the difference? Which should we use?
The docs here could use an update with more general explanation of what, how and why is this plugin used.

Thanks!