Also, it provides an opportunity for a team presentation. It is best not to present a proposal to a large group alone. You become an easy target. A presentation team broadens your base, varies the communication style and adds layers of multi-disciplinary expertise. There are several reasons.
Graphics help listeners understand abstract concepts.
Complex data can be organized and compressed in a chart or table to make a point clearly and concisely. Use graphics with both the verbal and the written presentations. It does not matter that they are redundant because the context in which they are presented differs. Visuals communicate swiftly and powerfully but do not over use them. For a 20 minute presentation, five or six is the limit.