The plugin documentation standard was created to address the frequent complaint of lack of documentation, specifically for the Maven plugins. The standard was based on suggestions made on the Maven dev mailing list with some refinements. It is a community consensus of what basic documentation a Maven plugin should have.
The standard is not a set of rules but a guide to help plugin developers document their plugins better, for the benefit of the users of the plugin. The standard also reminds the plugin developers of the important details that needs to be documented, to help speed up the adoption of the plugin.