0. Cross-platform (I use ZFS on Linux, FreeBSD, and [previously] macOS).
1. Pervasive check-summing/scrubbing, protection from silent bitrot
2. Low-cost COW snapshots (which can be directly accessed with ~/.zfs/snapshot)
3. Steaming file system state with zfs send / zfs receive (this is super important for backup and replication)
AFAIK, no other FS has all of this.