PowerPoint is a presentation tool, and like any tool it can be misused to the point of frustration. At best, PowerPoint offers a good way to provide a visual aid for a presentation. People who present crappy PowerPoint decks would have no trouble delivering a similarly crappy speech, or writing an indecipherable memo.
One great book on delivering awesome presentations - Presentation Zen (http://www.amazon.com/Presentation-Zen-Simple-Delivery-Editi...)