I used both and even though their purpose is very similar (have an "immutable" system tree that you create and switch into it), the day to day is very different.
Silverblue is still pretty much imperative, you install/remove RPM packages and that's it, you use Flatpak for everything else. NixOS you have to describe your entire system in a programming language. NixOS gives you so much more freedom to do what you want, but you have to work for it, learn a language, learn it's constructs, etc.
I enjoy both though, feels like the right direction to go, you just need to choose how you want to interact with your OS.
I haven't tried, but I get the sense that those are more about cleaning up the run time than the build process. At least the flatpak/snap world also is kind of anti-integrative in that everything is vendoring everything else.
I personally think containerization is just too much a PITA to use for software that doesn't live in a bubble, e.g. desktop software. The capabilities revolution (Capsicum or CloudABI) would be more secure and easier to program with, so we just need to force our way there, and then everything will take care of itself.
Nope, but it's not the same thing. NixOS can easily provide me with free rollbacks and is mostly reproducible (https://r13y.com/). The funny part about NixOS is that once someone reports a weird behavior, almost everyone will have it and can verify/fix.
Silverblue is still pretty much imperative, you install/remove RPM packages and that's it, you use Flatpak for everything else. NixOS you have to describe your entire system in a programming language. NixOS gives you so much more freedom to do what you want, but you have to work for it, learn a language, learn it's constructs, etc.
I enjoy both though, feels like the right direction to go, you just need to choose how you want to interact with your OS.