Yeah, you can if you plan well enough (typically. What I’m trying to illustrate is that this works by taking a snapshot of the disk in time. It’s like keeping a working copy of your system on your disk to be able to revert to.

While with NixOS you work with a “recipe” how your system is supposed to be configured. It is much lighter. It is declarative, you change the recipe and get what you described, you change configuration and all packages which you did not mention and are not used by anything are gone. If you update your system you can use the same configuration on it

The thing is that using can still get BTRFS or ZFS and use it to have snapshots too (for example your home directory)