Comment by imiric
The scenarios you mentioned are indeed nice use cases of ZFS, but other tools can do this too.
I can make snapshots and recover files with SnapRAID or Kopia. In the case of a laptop system drive failure, I have scripts to quickly setup a new system, and restore data from backups. Sure, the new system won't be a bit-for-bit replica of the old one, and I'll have to manually tinker to get everything back in order, but these scenarios are so uncommon that I'm fine with this taking a bit more time and effort. I'd rather have that over relying on a complex filesystem whose performance degrades over time, and is difficult to work with and understand.
You speak about ZFS as if it's a silver bullet, and everything else is inferior. The reality is that every technical decision has tradeoffs, and the right solution will depend on which tradeoffs make the most sense for any given situation.
How often do you test your OS replication script? I used to do that too, and every time there was always something broken, outdated, or needing modification, often right when I desperately needed a restore because I was about to leave on a business trip and had a flight to catch with a broken laptop disk.
How much time do you spend setting up a desktop and maintaining it with mdraid+LUKS+LVM+your choice of filesystem, replacing a disk and doing the resilvering, or making backups with SnapRAID/Kopia etc? Again, I used to do that. I stopped after finding better solutions, also because I always had issues during restores, maybe small ones, but they were there, and when it's not a test but a real restore, the last thing you want is problems.
Have you actually tested your backup by doing a sudden, unplanned restore without thinking about it for three days before? Do you do it at least once a year to make sure everything works, or do you just hope that since computers rarely fail and restores take a long time, everything will work when you need it? When I did things like you and others I know who still do it, practically no one ever tested their restore, and the recovery script was always one distro major release behind. You had to modify it every few releases when doing a fresh install. In the meantime, it's "hope everything goes well or spend a whole day scrambling to fix things."
Maybe a student is okay with that risk and enjoys fixing things, but generally, it's definitely not best practice and that's why most are on someone else's computer, called the cloud, as protection from their IT choices...