I interpreted your statement of "just to have plenty of backup" as having plenty of storage space rather than multiple copies / redundant backup.

The problem I have had is that when one is trying to duplicate/copy > 1 Tb of data across tens, if not thousands of files, that the bitrot is not always easy to find. Windows and OS X / MacOS treat bitrot differently and, it seems, across different file types.

And yeah, lots of issues with scratching, discolouration, lost, etc., of any printed or optical media. That's why a hybrid physical-digital solution is a good half-way house. Same goes for encryption keys or one's crypto wallets, best to hedge one's bets over physical and digital media.