If you have a digital camera you can even attach so images. But not all government official are equally comfortable with the medium yet. It is hard to determine when it is being read. On serious issues, in-person meetings provide opportunities to negotiate. This can work both ways, depending upon your skills at negotiation.
Some people have trouble staying firm and cede more than they had intended.
Also, unless you make a special effort, there may be no written record of the outcome of the discussion. Even if you don't have a specific issue to discuss, it is sometimes worthwhile to make courtesy calls on public officials to help build rapport. Public officials are very busy, so if your visit is a courtesy call, make sure that is understood and limit your stay to ten or fifteen minutes. Making a personal visit you have the advantage of being able to notice things on the official's desk or wall that give clues to common interests that you can talk about. Attending public meetings is rarely sufficient but in the age of citizen participation it is necessary to validate your position.