They do very different things even if the outcome is the same. You are not rollingback your system by downgrading each package. You are statefully changing your filesystem. Rollbacks in Nix and Guix are internet free, atomic and reproducible because they amount to changing the target of a single symlink
A little too pitchy imho. It is just a regular linux distro with each system update creating a new fs snapshots .
Just use Nix/Guix lmao