The open shelf design will make the space cluttered and reduce the sense of space when it is full of things.
Using the cabinet door for concealment not only can cover up the clutter, but make the space feel more tidy. It can visually maintain a sense of neatness and the sense of space will be better.
Using the door to cover the places other than the TV, when watching TV, your eyes will not be distracted. Your focus can be fully on the screen.