CREATE OR REPLACE PACKAGE BODY demo
AS
   FUNCTION f1 RETURN NUMBER IS
   BEGIN
      RETURN 1;
   END f1;
 
   PROCEDURE proc1 IS
      x   NUMBER;
   BEGIN
      x := f1;
   END proc1;
 
   PROCEDURE proc2 IS
      x   NUMBER;
   BEGIN
      x := demo.f1;
   END proc2;
END demo;

Depends on the level "tightness" you want in the code base.

Let's assume you *just* have function f1 and proc2 in the package. (ie, no proc1).

If you have a standalone function called "f1", then if you were recreate the package *without* the internal function "f1", then proc2 will *still* compile happily, but is now referencing the standalone function f1.

That *might* be what you want...it might not be.

So you could argue that the package name prefix makes the code more robust, but in my experience, I've rarely seen it done for intra-package calls.