Zfs has a lot of features over ext4 its not remotely equivalent.
Replacing this functionality on ext4 requires an entire stack of alternatives. Worse if you opt to use zfs and ext 4 you now need 2 complete stacks or to use an inferior set of tools to be compatible with a commodity service.
Replacing this functionality on ext4 requires an entire stack of alternatives. Worse if you opt to use zfs and ext 4 you now need 2 complete stacks or to use an inferior set of tools to be compatible with a commodity service.