SQL & PL/SQL

WITH t AS
        (SELECT MAX (lDATE) tidate
           FROM rate_Master
          WHERE     Code = 'G'
                AND orno > 0
                AND TYPE = 'L'
                AND lDATE <= ':entereddate')
SELECT DECODE (:p1,  'B', RateB,  'S', RateS,  Rate)
  FROM rate_Master, t
 WHERE     Code = 'G'
       AND orno > 0
       AND TYPE = 'L'
       AND NVL (lDATE, SYSDATE) = tidate;

In the given example the sub query returns just one row because of the aggregate function max. Making this in to a With clause will be of any benefit ? Also i presume/understand that the subquery factoring would be really useful only when we try to make a sub query which returns more rows in a with clause. Is my intrepration right?

Secondly adding the /*+ Materialize */ hint to a With query is mandatory or the optimizer by itself will do it and make a temp table transformation. In my example i am forced to give the hint in the query. Please discuss and help

Thanks in advance.