Cd/DVD discs are enough for me to hold my coins for the long term.
I have had many CDRs that were useless after a few years. Some are still okay, but I'll always asume they won't last.
The archival ones are bound to last longer, maybe even 100s of years due to being built with silver. Unfortunately, it's still speculation. The longevity of the disk isn't the only consideration, one also needs the reader. I've never had a reader/writer last over 10 or so years, and since they sit unused most of the time it'll be when you need it immediately that you'll realized it has stopped working. Imagine 20 or 30 years from now, how little demand there will be for optical disks, which means higher prices for reading hardware. Possibly making it very expensive just to read your archives.
For long term storage, I trust paper much more than anything digital. My solution for Bitcoin Core's wallet.dat is only to keep it as a hot wallet, and don't keep much in it. I have backups too of course (on external HDD and USB stick), and regularly make new backups (even though that's not necessary, it's part of my normal backup routine).
I agree with you about the paper and using core as a hot wallet. Even though you can use the hdseed to back up the wallet, I would want it on paper and I've yet to see it as worth the trouble/potential risk. I'm much more likely to make a mistake while transferring an hdseed to paper than I am if transferring 24 common words.