Well, if a Game doesn't have those settings it is necessary. Now, most new games have the proper options, but some do not. Mainly I use it on older games, like (first one that comes to mind) Oblivion that does not allow you to use HDR and AA, even though modern cards are quite capable.
Another option is to set the level of Driver level optimizations. This is something the game cannot do, and I do not know what drivers alone would default to.