RAID would be cheaper (and faster and more reliable).
Simply using two identical disks and RAID1 would take care of the hardware failure in most cases, usually for less money than this costs.
Also disk recovery is not a sure thing. The RAID1 is.
Neither protects you against filesystem corruption, user error, malware, etc, but that's what backups are for and not something this product claims to cover either (It can't after all).
The RAID1 option also doesn't expire in 3 years, and can continue to work after a failed disk is replaced. Much cheaper long term, and you can continue using your computer when a disk fails, rather than wait for data recovery to (maybe) happen.