Hello Theod,
Let us take an example. User 1: scott, User 2: todd. Say I am scott and you are todd. Say the administrator has given me (scott) to execute as well create/alter/drop todd's procedure/functions/packages then I do not need to login as todd to do that. I can login as scott and still compile/read todd's package.
If you give a good look that feature is already available for the Target Schema but not the source schema.
If you are still unclear please let me know.
Thanks,