The scenario plays out like this. To the rescue, a laminated job aid passed out as handout. The mind processes new information at different speeds depending on the medium. The answer is that presenters convey much more than words when they speak and more readily connect emotionally with an audience than via writing. The spoken word makes a connection and tells a story.
Text supports and expands ideas with details and applications.
Why poor handouts get tossed. Be an integral part of the presentation. Support the audience's future use of the presentation. Package the information from the perspective of the audience or user. Sift and focus the information.