[Disclaimer: biased Flox/Nix person]

There's a lot of reasons to use Nix instead of or WITH Homebrew depending on your exact needs.

Where it’s paid off for me (and where I think it actually wins) is when the problem is recreating environments: multiple machines, teammates, CI, nasty native deps, CUDA stacks, etc. At that point you’re choosing where entropy lives: in invisible drift (brew/manual installs) or in a repo you can diff/rollback.

Also, you don’t always need to go full “immutable everything.” Really depends on your needs here. Hybrid tends to be another sane path. In certain situations this can get you 80% of the upside without having to rip it all out. So kinda the "good enough" which I've seen a lot of folks do.

We (Flox) actually worked on this with Kelsey Hightower a while back - https://bsky.app/profile/kelseyhightower.com/post/3ld2rsccls...