Yes, it's radically different. The difference is similar to that between ext4 and btrfs or ZFS.
It replaces HFS+, which itself predates macOS/OS X and over the course of its life got a lot of Unix-specific modern features bolted on in the form of various clever/scary hacks (e.g. hard links).
This seems like goal post moving. The question was if the migration was complicated, the answer is yes.
Whether or not APFS is revolutionary or the best option is not the discussion. The core fact is that Apple needed to move away from HFS+ and they decided to move to their own FS, which brought in a bunch of changes that are standard in other OSs.
And they did it in a smooth and fairly uneventful way, so that's remarkable.
No smartphone these days gives you access at the mass storage level anymore (because it causes issues for concurrent access from the phone and computer, because there's often encryption etc.), so the underlying file system in this scenario is completely irrelevant and has no bearing on you being able to access the phone's data on Linux.
Android uses MTP or PTP (can't remember which) for that type of access, while iOS uses something proprietary, but there's a Linux implementation that worked reasonably well for me last time I had a Linux laptop: https://libimobiledevice.org/
You're way offtopic just because you wanted to be all dumb and tribal. Nobody claimed APFS was better than your favorite filesystem, simmer down.
But also, I wanted to let you know that even in your tribalism you're being stupid. AFPS is not a clone of ZFS. Not even close! It has a fraction of ZFS's features. Why? Because it doesn't need them. Why? Because Apple is tightly focused on client devices, and those do not need the huge list of server-oriented ZFS features, or the overhead that comes with them. And that overhead is considerable! People are often advised that 8GB RAM is the bare minimum for a server running ZFS filesystems, and much much more RAM is desirable for performance. Apple deployed APFS to iPhones with as little as 1GB RAM. ZFS was simply not an option.
APFS is its own thing. Deal with it.
Also, your whole schtick here sucks. Only one FS gets to be "FIRST!" at anything. Other filesystems which implement that feature are not necessarily "clones". To actually make the judgement that cloning occurred, you'd have to get real technical and look at both the algorithms and the on-disk layout, and if you actually did this there is no way in a million years you could come away thinking APFS is anything other than original work.
Ideas? Well duh, people build on other people's ideas all the time. If idea stealing was completely forbidden, once Gutenberg invented the printing press, nobody else could have built them, and where would humanity be now?
It replaces HFS+, which itself predates macOS/OS X and over the course of its life got a lot of Unix-specific modern features bolted on in the form of various clever/scary hacks (e.g. hard links).