Unless you assume that all hardware is perfect and that no bugs exists in ZFS (have been plenty of those in the past that just makes the whole FS completely worthless).

Nut no, ZFS doesn't need fsck. Because, we don't want it to need one. Oh, and we don't want to spend the resources developing one.

The only reason ZFS doesn't have a fsck tool is because in the enterprise world it doesn't need one. When it is needed you just restore from tape instead. It is that simple.