Keep in mind that if you set up raid using zfs or btrfs (idk how it works with other systems but that’s what I’ve used) then you also get scrubs which detect and fix bit rot and unrecoverable read errors. Without that or a similar system, those errors will go undetected and your backup system will backup those corrupted files as well.
Personally one of the main reasons I used zfs and now btrfs with redundancy is to protect irreplaceable files (family memories and stuff) from those kinds of errors, as I used to just keep stuff on a hard drive until I discovered loads of my irreplaceable vacation photos to be corrupted, including the backups which backed up the corruption.
If your files can be reacquired, then I don’t think it’s a big deal. But if they aren’t, then I think having scrubs or integrity checks with redundancy so that issues can be repaired, as well as backups with snapshots to prevent errors or mistakes from messing up your backups, is a necessity. But it just depends on how much you value your files.
Unironically why I switched my parents to Linux - they don’t touch any important settings so usually the only problems are when they get a new popup / prompt they’ve never seen, which ofc happens a lot more on windows especially when they decide to push some new thing or decide that they want to convince people to enable something new or change a setting that they want people to use.
I also love that if they call me I can just ssh in over tailscale and do whatever needs doing.