A good novel has multiple levels of depth, the basic story, below that the deeper themes.
In presentation design I often apply similar techniques. The top level message screams from the chart through the use of colours (target: the listener), but for the reader, there are ways to find richer information to back up the bold conclusions you draw.
One example could be a simple table of pros and cons. Big colour contrasts indicate "in favour" and "against" for each of the criteria, but small text inside the boxes that is not meant to be readable for a live audience gives the more detailed explanation.
For TED-like big budget presentations, you it is worth to take out the detail. But most business presentations are used in multiple settings, it is just more efficient to have one set of slides supporting both of them.