Most of the time that is about as much as the pitch will ever need to be changed, though. It still comes down to the person speaking. If you are incapable of making your voice sound different then a pitch changer will not take your project far at all. But he seem to be able to pull that off so the range of a single octave give or take, is good enough. When I animated a monolog of Morgan Freeman I could make the voice but not at the depth of the actors voice. Pitch alteration applied and it sounded completely like him.

If your not trying to impersonate an actual person, then it's that much more beneficial and I wouldn't see why anyone would not prefer pitch alteration software. It's much easier then finding the people willing to act for free or even capable of voice acting. In my experience, it's hard to find people that will do it for nothing let alone have the necessary talent and not just read their lines as if it were a shopping list :)  My point being, use any and all talents and tools available. And yes, spend the money and get a quality microphone with a filter.