Slight correction to Reddo's comment: In Oz you may only exercise the privileges of a licence, rating or endorsement once it has been issued. Therein lies the rub. Ratings and endorsements may be issued by an approved person, in which case they can be used immediately that person signs the sticky label.
Licences however are the preserve of CASA, and CASA alone. You can't exercise the privilege of the licence until it's issued. CASA are the only ones who can issue licences so you have to wait until they do their thing before you can go play.