While slide shows like MS Powerpoint have their pros and cons, there is a risk in not having any slide show to help your audiences.
Stephanie Everett‘s Lawyerist article Lawyer Public Speaking & Teaching addresses this and related issues in her great short summary of the topic. It’s all worth reading, and these points are particularly relevant:
Audiences almost always expect a slideshow when they attend a presentation. Without it, they may think you forgot or were just too lazy to put one together. …
The slides should be the starting point for a conversation. This will help frame your topic and remind people where you are. …
The audience is there to hear you and not to read the entirety of your presentation from slides. Keep the information on the slides limited, and make sure you are the one giving the lesson, not the slides.
Finally, have a backup plan. Computers crash. Flash drives get corrupted. Your presentation may not work. That means you need to be ready to roll without the aid of a PowerPoint slideshow.