Why do we use RMAN DUPLICATE for cloning DB on a different server ?

Question

DB version : 11.2.0.2, 10.2.0.5
I want to create a clone of my Production DB in a test server. In the past, I have taken hot backup of this production DB and restored and recovered it in a different server using plain RMAN commands.
After restoring the control file , mounting the DB and cataloging the backup pieces in the test server , I run
run {
restore database ;
recover database until time <time> ;
alter database open resetlogs ;
}In OTN , i came across long running discussions like
RMAN duplicate database
where they are trying to restore and recover using DUPLICATE command as shown below.
run
duplicate target database to RBS
nofilenamecheck
pfile=/tmp/aux.ora;
Can't they just use plain RMAN restore and recover commands as I did ? What advantage does RMAN DUPLICATE have over the plain commands ?

Answer 1

RMAN DUPLICATE is designed to give to clone database a new database name and new database identifier:
>
If you copy a database with operating system utilities instead of the DUPLICATE command, then the DBID of the copied database remains the same as the original database. To register the copy database in the same recovery catalog with the original, you must change the DBID with the DBNEWID utility (see Oracle Database Utilities). In contrast, the DUPLICATE command automatically assigns the duplicate database a different DBID so that it can be registered in the same recovery catalog as the source database.