Most CDs/ DVDs / BluRay are not archival either, though there are archival quality ones on the market but those are typically out our your and mine's budget.

For backups, I backup multiple different ways, sync'ed between multiple devices, hard drive in an external case, USB flash or other flash device, cd/dvd/bluray.

I used to keep some offsite but I kept having to explain to my parents that I intended to leave those there but she would still tell me once every couple weeks that I forgot something.