[keeperofdakeys]

Because ZFS has one of the most robust RAID systems in an opensource filesystem, and is incredibly mature.

And to be fair, almost every file system will have degraded performance and increased fragmentation above 80/90% full, so this should be considered universal advice.

There is also a legitimate question of how wide spread the issues are with the ZFS encryption feature. The fact this hasn't picked up much steam implies its not a common issue.