ZFS can help you with backups and data integrity beyond what RAID provides, though. For example, I back up to another machine using zfs's snapshot sending feature. Fast and convenient. I scrub my machine and the backup machine every week, so if any data has become damaged beyond repair on my machine, I know pretty quickly. Same with the backup machine. And because of the regular integrity checking on my machine, it's very unlikely that I accidentally back up damaged data. And finally, frequent snapshots are a great way to recover from software and some user errors.
Of course, there are still dangers, but ZFS without backup is a big improvement over RAID, and ZFS with backups is a big improvement over most backup strategies.
Of course, there are still dangers, but ZFS without backup is a big improvement over RAID, and ZFS with backups is a big improvement over most backup strategies.