For some people, whether or not to use powerpoint is not even a question. It is assumed. I don’t assume I should use it. My default is no powerpoint, then if I use it, I use it on purpose.
I think it may be worth using if there is an image that will really help, such as a biblical map, image or a contemporary scene of significance (the person to go with the quote, etc.), or if there is a series of verses away from your preaching text that you want people to see quickly (have good reason for sharing multiple other verses), or if there is a movie clip that will reinforce and help (but not overwhelm) the message. I only think it may be worth using if either you or another person can design it and control it perfectly (clear and consistent fonts of the right size, very limited use of words, transitions that work to the millisecond both coming on and going off, etc.) Sadly, often even appropriate powerpoint material is sabotaged by very amateurish use.
I don’t think it is worth using in order to show your outline (that’s for you, not them), or to show your preaching text (they need the practice reading their own Bibles). I don’t think it’s worth using if it means sacrificing preparation time for formatting time. I certainly don’t think it’s worth using just because you have a projector and a laptop. I don’t think we should use it just because it is used in the business world (please note many in the business world are lousy speakers, and many of the good ones left compulsive powerpoint use behind years ago!) I’d rather have listeners engaged with me and with the Bible in their laps than with a screen.
Haddon Robinson has said that, “A picture is not worth a thousand words (the people who make pictures came out with that!) Some words will never be captured in a picture.”
Powerpoint may be helpful. Steve Mathewson has written that he periodically has a powerpoint enhanced sermon, but he never has a powerpoint driven sermon – amen! If you use it, please be professional, be subtle, don’t turn to look at it yourself or even refer to it unnecessarily, don’t overload the screen and don’t lose sight of the fact that it is you who is called to be the preacher, not the screen.