For pirated movies, I meaaan... linux ISOS, is fine not to have backups cause as you said you can re-download them. My SSD with all my jellyfin media died recently and it kinda sucked but at least I didnt lose anything important.
I guess most people in this sub that have redundancy with their media is because they rip the movies out of blu-rays they bought rather than download it. I also save copies of my ripped (legally) videogames.