The snapshot-only job is similar to scheduling automatic snapshot creation in the storage management console. A snapshot-only job does not create Veeam backup files on the backup repository. It creates only storage snapshots on the storage system by schedule defined in the job settings.
You can use snapshot-only jobs to create a snapshot chain on the primary storage array where disks of VMs processed by the job are hosted. In addition to it, you can instruct the snapshot-only job to create a snapshot chain on secondary storage arrays.
Depending on the backup job settings, the created snapshots can be application-consistent or crash-consistent.