You will need to double check the specific DVDs you are working with. They can be useful for backups and if you don’t store them in sunlight or acid or something they basically last forever. You can copy your important data onto a DVD and leave it in your closet for the rest of your life. Of course, as with all backup strategies, you need to test it very regularly.
Edited to add nitpicks: if you decide to do this back up across multiple DVDs and use encryption. Borg is a fantastic tool for encrypted backups and if you are just mounting your DVDs as cdrom0 and such it can handle that as easily as any other block device.