> Modern file systems like ZFS, which Apple considered but abandoned as a replacement, include checksums of all meta data structures. That means that when the file is accessed, the filesystem detects the corruption and throws an error.

This is exactly backwards - metadata checksums don't protect file contents. They just cover the integrity of the FS so when the FS internals are corrupted, it knows not to write to random places on the disk and can with redudancy can try to recover the metadata.