That’s not entirely true, unless you choose to nixify everything. You can just have a basic Nix configuration that installs whatever programs you need, then use stow (or whatever symlink manager you prefer) to manage the rest of your config.

You can’t entirely forget that you’re on NixOS because of FHS noncompliance but even then getting nix-ld to work doesn’t require a lot of effort.

The mentioned performance governor runs the CPU permanently at maximum frequency, which is obviously bad on battery powered devices and on devices with lacking thermal headroom. I think it might cause problems in virtualized environments as well but I’m not sure about that.

To be fair showing the overview on startup makes perfect sense on vanilla gnome, it’s only dumb if you install one of the two specific extensions that partly replace it.