I disagree, having slides allowed me to quickly learn all the material, much faster than if I was actually attending class. This freed up all my time to get work done and enjoy life in college.
What you would actually want to use in such a case are lecture notes. Or from a different angle, those slides you used have actually degraded into lecture notes and are thus necessarily worse as presentation material.
Only works if slides don't omit important details or you are re-visiting the slides after having prior knowledge. Some ppts are more like visual aids (outlining important points in a few words) yet doesn't provide any detail. I enjoy both slides and audio. They compensate each other, provided that you have an articulate speaker... Whenever I read slides with proofs I rather have an audio stepping through the entire proof. Staring at proof or some data flow diagram doesn't convey enough to me.
