I would hope that the answer is obvious: landing on a carrier, decommissioned or not, is NOT PRACTICE!  Carrier landings are delicate hand-eye reflex coordination, much like a concert pianist.  In order to maintain the necessary level of proficiency practice is essential, again like a pianist.  

If a pilot has been away from the carrier for a period of time practice is essential to regain the required level of proficiency.  So a number of practice sessions are required by the Navy before a pilot is allowed to make a real carrier landing.  Remember, landing on a carrier is an extremely dangerous activity.

Stan Stanley. (820 carrier landings, thousands of field practice landings)