ZFS still gives benefits with one disk. Ignoring the data integrity stuff (which is better with ZFS even if you have no ECC), you also get snapshotting, potentially boot environments, you can backup your data to another machine using zfs-send, you get native encryption (including encrypted backups for free), highly performant compression, and (depending on your system) a nice memory cache algorithm.

It’s actually quite useful for laptops.

Checksums if the mobile hardware is damaged, snapshots if you delete something in your daily driver, native encryption if laptop is stolen, backup of work data via ZFS send if you have a ZFS server, compression to use limited disk space in laptops, errors can be fixed with copies=2, etc.

On my FreeBSD Thinkpad X220 there are two SSDs running a ZFS mirror. Why? Why not!

I allocate all my SSD space to one ZFS pool and then:

- I can easily create new subvolumes (filesystems or block devices), for different mount points, containers, other distributions, VM disks...

- The free space is shared between all of them, no need to anticipate a partitioning layout

- I have a service that automatically snapshots some of them, others not

- I love the ZFS tools, I'm very happy to use them on all my machines

- I use NixOS everywhere and so it's also easier to share the same conf on all my machines

- I can send volumes easily from one machine to the other (zfs send)

I probably miss other things, but I also love consistency ;)