The use case is that when importing a workflow from the Development tenant to the Production tenant, the workflow is in draft state. The Configure Workflow dialog is used to configure environmental configurations (e.g. SharePoint Online tenant URL) before publishing the workflow. Since the workflow design has changed in the DEV tenant, the requirement is to specify a version comment before publishing in the Production tenant. Since the Configure Workflow dialog does not provide a field for version comments, the workflow must be edited in order to update the SharePoint tenant URL and publish the workflow to specify Version comments.
The Version Comments field is only available in the publish dialog when editing the workflow design. The Configure Workflow feature requires a Version Comments field to allow workflows to be configured and published without opening the workflow design.