Having multiple backups is also fine but for long-term DVDs is way better to handle files for more than 10 years because I have a DVD that still survives after 10 years it still works.
I have SanDisk that I bought since 2018, despite the large files of about 40 gigabytes on it, it is still working till today. Although, I hardly use it.
As LoyceV comment, I think it is better that way. People should not depend on any device for long term storage. I understand you and I think that you are also right, and disks are also different from one another, there are some with even longer lifespan. But people should not depend on that because any device can fail at anytime. I year backup dependency is enough in my opinion.
I prefer seed phrase with passphrase and it makes backup easy for me on just a paper.