Yes, valid points that I didn't really want to muddy the discussion with. In my experience, most people hear the Redundant in RAID and think that's sufficient and that their data is safe. Maybe poor choice of words on my part, but that's what I meant re: "data safety."

You're fully correct that a proper RAID setup can provide additional layers of availability atop a robust backup process, but I'd wager most of the people who are interested in that extra layer are already aware of the limitations of RAID.

I do run RAIDZ1 on my franken-nas due to limited drive sizes on that machine, the goal being to maximize usable space while providing a sufficient amount of time to address a drive failure. If drive prices ever become reasonable again, I'll likely rebuild the system with 6-8 drives in a RAIDZ2 configuration just for a little more peace of mind, but as long as my off-site backups are running, I sleep at night just fine.