As well as hardware control including their own controller which may implement more ECC under the hood (and I'm 95% sure I remember that part of the reasoning f

As well as hardware control including their own controller which may implement more ECC under the hood (and I'm 95% sure I remember that part of the reasoning for lack of full checksumming in APFS was "well our hardware doesn't have those errors"), 9GB also isn't actually that much even over tens of millions of systems. ZFS is used with an absolutely massive variety of hardware from expensive to cheap, with petabyte levels of data (or more at this point) in single installs. I've seen some real weirdness with APFS on non-Apple storage devices, and corruption crept into some of the data stored on my Macs somewhere in the decade before I started using ZFS (images I know were fine in the 00s with data errors I found much later, there is probably other stuff but of course the whole problem is that I don't know and have no great automated way to find out). This isn't dunking on Apple putting together a reliable product in their own walled garden using their own full array of vertically integrated options at all, but at the same time the ZFS team can be entirely correct given a very different problem space.