Or:

    guix install ungoogled-chromium

This CLI difference is in part due to the underlying design, which is not just about syntax (parens vs. braces) but more about abstractions and composition.

For example, the Nix language doesn't have the ability to define new data types, and it doesn't have a "package" or an "operating system" data type. That means that all the entries in Nixpkgs look alike, which in turn prevents building a "package-aware" or "OS-aware" user interface.

The Guix CLI "knows" about packages and versions, and package transformation options are an example of how the CLI can take advantage of that abstraction.

Likewise, the "guix system" command knows about services, which gives it convenient introspection capabilities such as "guix system extension-graph" and "guix system shepherd-graph".

It really isn't about parentheses vs. braces. :-)