"in areas as diverse as X, Y, and Z" highlights the diverseness of the different areas. it is stronger in meaning than the alternative of "in the areas of X, Y, and Z".
"as many/much/great/etc as" and "no less/fewer/smaller/etc than" are commonly used to emphasize a point.
1. Ten people died in the accident - factual with no emphasis.
2. As many as [No fewer than] ten people died in the accident - emphasizes the large number of fatalities.
1. He won gold in four events.
2. He won gold in as many as four events = He won gold in no fewer than four events = He won gold in four events, which is a large number.