Why can't you? Granted, you need enough disks to actually have all the data - so ex. if you did RAID0 then yes you need all disks, but say if you did a mirror you can totally just yank a disk out, attach it to another machine, and `zpool import` it.
* https://utcc.utoronto.ca/~cks/space/blog/linux/ZFSSplitPoolE...
Only with mirrored drives.
Any RAID-Z level would need a full export/import as data is striped, but hot-swap drives can be pulled once things are unmount.
I agree that it can be a bit daunting to operate, there are a few footguns around that, while it might not lead to data loss, but can lead to unfortunate situations.
Just the other day someone on the mailing list had managed to add a single drive as a new top-level vdev to a petabyte pool, rather than adding it as a new spare drive, simply by omitting the word "spare" from the "zpool add" command...
That said, I've been using ZFS at home here with 6+ disks for almost a decade now, and I've never lost data despite lots of various incidents, including lots of power losses and various hardware failures (like disks, mobo and PSU). So overall I'm very happy with it.
ZFS has... a lot more. It’s just very different and the way these states fit together, and worrying about how to operate on them safely, makes me more nervous, in many ways, than less-safe file systems do. I’m sure that will pass, but it’s still not fun.
For me I found it beneficial to watch the videos on how ZFS is built up, like this one[1]. Helped putting the pieces together.
EDIT: It'd look like this: https://serverfault.com/questions/964075/how-can-i-recover-m...
When I say "corrupted beyond repair", I mean "the btrfs tools were not actually helpful".