For example you might want to hide Categories and Tags metaboxes for your Contributors and allow only Editors to manage them. With AAM plugin you can hide any registered metabox or widget on the Metaboxes & Widgets tab by simply selecting those metaboxes.
Some metaboxes are conditional and appear on the edit screen when certain conditions are met. For example metabox “Comments” appears only for existing page or post and not for new. If you do not see a desired metabox, try to copy & paste the full URL to the backend page where that metabox appears.