The storage medium you choose really isn’t as critical as making multiple copies, storing them in separate physical locations, and testing that you can recover the data when you need it. Diversity in the physical medium you choose is probably a good thing too long term. Archival discs aren’t really that long lived though. You could try, but unless you are regularly checking the discs and making additional copies, you’re going to loose data eventually. I gave up using discs as any kind of backup because it was too much hassle. Copying hard drives was much more straightforward and reliable.