I took a quick read of the article. It's good. It makes some excellent points (that I've made myself) about how PowerPoint can be a detriment to worship and preaching. Murphy starts off by quoting Edward Tufte: "Power corrupts, PowerPoint corrupts absolutely." I think that Tufte brings up needed critiques of, what he calls, "the PowerPoint cognitive style" which is a reduction of ideas to bullet points on a slide. That style of "death by PowerPoint" needs to be rooted out from every classroom, conference room and pulpit. It leads to less understanding of the material by both the presenter and the audience.
So, Murphy is right when she says, "To use PowerPoint in worship is to unwittingly set up a competition between what's projected on the screen and the human voice doing the preaching, praying or singing." When PowerPoint is used in a text-based format, peppering the audience with pithy bullet points that attempt to reduce the irreducible, it is absolutely a competition between voice and screen.
However, Murphy either has never experienced or chooses to ignore the combination of images with speech. Copious neurological research underscores the fact that when the human voice is paired with complimentary images, retention and comprehension of the material rise dramatically.
"If information is presented orally, people remember about 10 percent, tested 72 hours after exposure. That figure goes up to 65 percent if you add a picture."That's a serious increase, and it's nearly impossible without PowerPoint. You could make your sermon 6.5 times more effective by adding a few pictures. That doesn't seem pointless to me.