From the Windows IT Pro Center documentation of the
wbadmin start backup option
-allCritical (italics by me):
Specifies that all critical volumes (volumes that contain operating system's state) be included in the backups. This parameter is useful if you are creating a backup for bare metal recovery. It should be used only when -backupTarget is specified, otherwise the command will fail. Can be used with the -include option. Tip: The target volume for a critical-volume backup can be a local drive, but it cannot be any of the volumes that are included in the backup.
Then there is the option
For Windows°7 [sic] and Windows Server 2008 R2 and later, creates a backup that includes the system state in addition to any other items that you specified with the -include parameter. The system state contains boot files (Boot.ini, NDTLDR, NTDetect.com), the Windows Registry including COM settings, the SYSVOL (Group Policies and Logon Scripts), the Active Directory and NTDS.DIT on Domain Controllers and, if the certificates service is installed, the Certificate Store. If your server has the Web server role installed, the IIS Metadirectory will be included. If the server is part of a cluster, Cluster Service information will also be included.
Am I right to assume that
-allCritical includes the data referenced by the option