Here are just some answers I was able to search through the web.
- First, the world is built of shape and space, and geometry is its mathematics.
- Second, informal geometry is good preparation. Students have trouble with abstraction if they lack sufficient experience with more concrete materials and activities.
- Third, geometry has more applications than just within the field itself. Often students can solve problems from other fields more easily when they represent the problems geometrically.
- And finally related point - many people think well visually. Geometry can be a doorway to their success in mathematics.
That's the most important part. But read the entire section from this site in the Related Link below