It depends what you're doing really. I run a 5 disk ZFS cluster to host media files. I'd rather not deal with failure very often, but when it does happen and I lose a whole bunch of media, I can download it again.
The second I elect to host anything even remotly important on it, it'll be backed up, but until then there's no need for me to pay to host that elsewhere.
Professionals who think they don't need backup's because they have redundancy do need a slap though.
Possibly, but what's the problem? It's pretty much a "just works" file system where you can lose 1-2 disks where blocks are continuously checksummed and scrubbed to ensure consistency.
The second I elect to host anything even remotly important on it, it'll be backed up, but until then there's no need for me to pay to host that elsewhere.
Professionals who think they don't need backup's because they have redundancy do need a slap though.