You are right. It can also be stated as below.
Export All > Exports all USER CREATED CONTENT ( and not those shipped out of the box ie certified contents) under the DESIGNER Portal which is nothing but workflows and its building blocks (ie Workflow, Finders, Filters, Commands, Templates, Functions, Dictionary Entry, Custom Data Source )
Database Backup > Includes everything ie, DESIGNER, EXECUTION and WFA Configurations
What each portal contains
DESIGNER: Workflow, Finders, Filters, Commands, Templates, Functions, Dictionary Entry, Custom Data Source
EXECUTION: Execution Status, DataSource Configurations, Reservations, Credentials Users
ADMINISTRATION: General WFA Configurations
Hope this helps.
Thanks to Abhi Thakur for bringing in the clarity on Export ALL. Only User Created and not those certified.