Yes its useful.
But when i start play Lineage 2 (C3) my pass was like my Acc.And one day me char was "nude" and it was set-ed to delete.From that day my pass is over 8 symbols a-z 0-9 :).
So remember Never gives your password to any one ... if he says "I am admin /GM give me you pass to test ... " you must write /gmlist and see if his name shows like GM just report to Admin :P if not just give him Wrong Acc and Pass :D