SQL & PL/SQL :: RESTRICT_REFERENCE Changing A Database State

When i am writing a function (Stand alone or inside a Package) i know what i am writing, i know weather i am changing a Package state or weather i am changing a Database State. So what is the use for giving a PRAGMA RESTRICT_REFERENCE?

as for the other PRAGMAs EXECPTION_INIT is needed to Specify an error name to a specifiec error number so that i can use the error name to handle the exception. AUTONOMOUS_TRANSACTION is used to execute the SQL Operation inside a Block as a child Transaction.SERIALLY_REUSABLE states that a package variable doesnot persists throughout the session.

RESTRICT_REFERENCE states that the code should not do the following
RNPS : Read no package state,
WNPS : Write no package state
RNDS : Read no database state
WNDS : Write no database state

what is there to state as i know what my code is doing.

without specifing EXECPTION_INIT, AUTONOMOUS_TRANSACTION or SERIALLY_REUSABLE i cannot get a handler for an exception which doesnot have a handler, i cannot execute SQL Operations from inside the CODE autonomously or i cannot reuse the package variable, but without the RESTRICT_ REFERENCE is can ensure that my code in not doing (RNPS,WNPS,RNDS,WNDS).