enable flashback database VS guranteed restore point

I read from Oracle online document: it says
You must have created a fast recovery area before creating a guaranteed restore point. You need not enable flashback database before you create the guaranteed restore point. The database must be in ARCHIVELOG mode if you are creating a guaranteed restore point.
Does that mean if I use flashback database to a guaranteed restore point, I don't need to turn on flashback on ?
and why is that?
Thanks

You don't need to turn on flashback manually because Oracle will turn it on for you when you create the guaranteed restore point (at least from 11g enterprise edition).

You can see this in the flashback_on column of v$database, which changes from "NO" to "RESTORE POINT ONLY" after the restore point is created:

SQL> select name, flashback_on from v$database;

NAME FLASHBACK_ON
--------- ------------------
FREE NO

SQL> create restore point my_restore_point GUARANTEE FLASHBACK DATABASE;

Restore point created.

SQL> select name, flashback_on from v$database;

NAME FLASHBACK_ON
--------- ------------------
FREE RESTORE POINT ONLY


After flashing back and dropping the restore point, flashback_on resets to NO.