So if nix could allow me to get the tools I need without context switching that would be a great addition. I don't want to have to go edit configuration files just because I haven't installed some tool yet.
Much quicker than a `brew install` for me.
I think under the hood home-manager basically declaratively manages a Nix profile for you. You (or even better a home-manager managed .bash_profile) can then put that profile into your PATH.
That being said, I think there are indeed ways to partially manage your config using simple command line commands but I haven't found the need myself.
Then for every dev project I have shell.nix defined which lists project's dependencies. I also have direnv installed, so when I enter that directory, the project's tools are automatically available for me. I rarely change the main configuration and more often project's shell.nix. And for one-off's I use nix-shell -p <package>
That's a pretty arrogant statement to make.