Yes, but ZFS is probably more memory hungry and somewhat an overkill just for compression alone. It's a pity simpler filesystems don't have transparent compression.

I'm not sure it's an overkill compared to the presented solution.

One disadvantage of zfs in this case is that it uses its own caching layer, since it's basically an OS subsystem in itself. So on a memory constrained host (eg. rpi), you might have some issues with the zfs and linux buffers competing for RAM.

Like NTFS has had for the last 20+ years? ;-)

One of the benefits of NT's packet-driven I/O model (versus the UNIX synchronous VFS read/write blocking buffer I/O model).

BTRFS is now good for it, but having it in other filesystems would be useful too. Linux now supports some async I/O as well.