Nix develop not using build-poll-interval?

Hello nix community,

I wanted to better understand the nix develop command.
I also wanted to play around with the interval that is used to poll for updates.

I am suspecting the build-poll-interval option to be relevant here, is this correct?
Unfortunately I didn’t find a resource explaining this option.

I also wanted to see what nix does if I execute

nix flake init --build-poll-interval 10000000

since the option is also listed here.

But the flake content doesn’t show anything related after being generated.

{
  description = "A very basic flake";

  inputs = {
    nixpkgs.url = "github:nixos/nixpkgs?ref=nixos-unstable";
  };

  outputs = { self, nixpkgs }: {

    packages.x86_64-linux.hello = nixpkgs.legacyPackages.x86_64-linux.hello;

    packages.x86_64-linux.default = self.packages.x86_64-linux.hello;

  };
}

Do I have a misperception on what build-poll-interval does or regarding the missing information in the flake.nix file?

I think I just understood one of my problems:
build-poll-interval is listed under “Options to override configuration settings”, so not relevant for the flake file content.

But still I am struggling with understanding how build-poll-interval works.

https://nix.dev/manual/nix/2.18/command-ref/conf-file.html?highlight=build-poll-interval#conf-build-poll-interval