DVDwrite is an archiving tool and not a backup utility!
Please think about the different objectives. The most common media for backup are tapes (DLT/LTOx). The read/write heads of the tape drive get in direct contact with the tape. You see this if you look at the tape durability: The durability of a tape depends on the number of reads/writes has to “suffer”! A unrecoverable read error leads to a loss the data that are behind the point of read error.
The data on an optical medium are read by laser light and never have a direct contact. There is no dependance of the durability on the number of reads and even if there are read error on a disk there are a great chances that the rest of the data are still readable.
There is an expensive error correction mechanism built in the drives to prevent data loss on an optical medium. The correction techniques were improved significantly in any technology that was developed later (CD ; DVD ; Blu-Ray).
It's clear that the maximal capacity of about 100 Gb of a Blu-ray disks is a limiting factor whether a archiving task with Blu-Ray disks are feasable. But two facts might help you to choose DVDwrite: it is possible to archive a bigger drive by the open source program called DVDarchive/restore that archives the drive in portions.
You want to get more information. Then select one of the two links:
DVDwrite for OpenVMS
DVDarchive/restore for OpenVMS