Why can't remote execution be achieved by simply creating a ScheduledTasks.xml file for a GPO scheduled task?

Simply creating a ScheduledTasks.xml file for a GPO only defines the task configuration but does not complete the registration process. The article shows that after creating the XML file, the scheduled task appears in the Group Policy Management Console but fails to execute remotely until a registration operation is performed. The registration step is required to make the GPO 'take effect' and actually deploy the task to target machines. See Domain Penetration - Remote Execution via Scheduled Tasks in GPO (Command-line Implementation Principles and Script Details) for the full details.