Pace.
With text I can proceed at my own pace and back up instantly if I think I missed something.
With audio or video, I am forced to progress at the presenter's pace and if it's too damned slow (and it often is) my mind will wander and I will definitely miss something.
So I have to figure out where I actually lost track of the presentation and relisten.
Again at the presenter's pace, not mine.
With text I can proceed at my own pace and back up instantly if I think I missed something.
With audio or video, I am forced to progress at the presenter's pace and if it's too damned slow (and it often is) my mind will wander and I will definitely miss something.
So I have to figure out where I actually lost track of the presentation and relisten.
Again at the presenter's pace, not mine.