I looked into the reliability of CDs a decade or two ago. The consensus back then was that the lifetime of writable CDs (as opposed to the plastic disks with mechanically stamped pits) was unknown, but probably somewhere in range of a few years to a few decades. Worse, to avoid royalty issues, every CD maker used a different proprietary dye layer with different characteristics. Back then, it was far from a sure thing that a CD written on one drive could be read back reliably on a different drive even before the disk aged for a few years.
I'm not saying that CDs aren't suitable for storage, just that one probably ought to do some research about longevity before committing to their use as an archiving medium.
Really, same's probably true of any media other than punched cards.