Bad explanation from a noob (me), but basically yes. Functions just always fit together and I don't need ugly sprawling interfaces or pointless declarations of nearly identical functions.
In Elixir when I want to pass a function with 3 arguments into an interface that expects 4, I can do something inline with no extra boilerplate like func(&1, &2, &3, <a default 4th value to be used in each invocation>)
Not your parent commenter but likely they at least partially meant that, yes.
Though that alone can't reduce LoC by 90%. Elixir is just incredibly terse and no-bullshit language in general. All the shorter code idioms together make for a readable and to-the-point code.