Comment by lilyball
> It seems very cool that you can roll back in the case of a catastrophic upgrade failure, but has that every happened to you? Not me.
Rollbacks saved me from completely destroying my entire system. I managed to fill up my boot partition in a way that deployed successfully but left the whole system unbootable after reboot, and the only way I managed to save it without having to completely wipe and reinstall from scratch (which means losing all my data) was to load the SD card onto my laptop, fix the boot partition by hand to ensure the kernel from the previous generation was valid, and edit the bootloader config to delete the offending configuration (because accidentally trying to boot it would re-corrupt the boot partition).
I've also used rollbacks in other less catastrophic situations, such as when I broke wireless (since I build remotely on a much more powerful machine and deploy over SSH).
I use NixOS on my home router and rollbacks also saved me from a Firewall misconfiguration that broke all network connectivity.