I rely on actions extensively to build functionality in my sites. I find them convenient for business logic because they are packaged chunks of functionality that can be called from many places, including Trigger, Rules, and VBO. Today, I've added a new place where actions can be called: the URL. Actions REST provides this functionality.
Consider a job site where a supplier receives an invitation to participate in a project. The supplier logs on the site and views the invitation, then wants to accept or decline it. Regardless of how the invitation status is coded in the back-end (e.g. via Workflow states or a CCK field), there are probably ready-made actions that can let you manipulate that state without coding. But, how to invoke such actions from the UI on the node? Actions REST provides half the solution: given that you manually code the action link (e.g., large red buttons "Accept" and "Decline"), this module will interpret the URL and invoke the action for you. It will also redirect the page back where you were, unless you specify otherwise.
I hope other Drupal heads find this module useful!