RMAN DUPLICATE command behavior for password files

When to use the option clause "PASSWORD FILE" in the RMAN DUPLICATE command ?

Password file in RMAN DUPLICATE command:

The DUPLICATE behavior for password files varies depending on whether your duplicate database acts as a standby database. If you create a duplicate database that is not a standby database, then RMAN does not copy the password file by default. You can specify the PASSWORD FILE option to indicate that RMAN should overwrite the existing password file on the auxiliary instance. If you create a standby database, then RMAN copies the password file to the standby host by default, overwriting the existing password file. In this case, the PASSWORD FILE clause is not necessary.