Why do some designers use empty white space in design layouts?

Otherwise feeling congested.

One real life example:

You are waiting for a vehicle for travelling. If the vehicle is arrived with full of people, you hate to get in and try to avoid it. The same thing happens in design also.

1 - to give the design balance and harmony between the elements imparted

2 - in order to focus on a particular content or emphasize it

3 - guide the eye from one element to another

4 - separation of the elements and create groups

5 - enhance the ability to analyze and read design

6 - give a sense of luxury and sophistication and elegance

7 - to create a space in which relax the eye