They make the work of mapmakers and navigators, statisticians and Geography teachers a lot easier. This is because it is easier to study the Earth when it is divided into equal parts.
The East and West hemisphere is less geographically obvious. Its a theoretical line drawn from the South Pole to the North Pole through the observatory in Greenwich, England. All the world from the Western side of this “Greenwich line” is regarded as the Western Hemisphere, and all the world from the Eastern side of this line is referred to as the Eastern hemisphere
