I noticed that the dialog for “Backup table as SQL dump” has more options than the icon for “Export as…” that can be used to create a sql dump for a custom query. Perhaps you could make it possible to also include those options in the “export as” dialog when the user chooses SQL as the output format. Or otherwise allow using custom queries for the “Backup table as SQL dump” dialog.
We deliberately did as we did with 'export as sql'. This was never intended for backing up tables (if you try you get a warning), but to export a result set. Result sets may come from different tables using different engines etc.