Maybe this arrangement of chairs has its advantages, but the main goal, in my opinion, is aesthetics, a pleasant appearance. Here are some examples. In most cases, these are new stadiums in national colors. flag.
As for the color. Often at matches, these chairs are taken away by the most active of the fans and used for other purposes. Chairs of a different color can be installed in their places.
Because this arrangement of seating during television broadcasts creates the impression that the stadium is more full. When focusing the camera on the field itself, the stands, which are often in Russia, Ukraine and neighboring countries (this is where this practice is quite popular when building new arenas ) are not one hundred percent filled, they look pretty dull. And blotches of chairs of one color on another color canvas visually "deceive" us, as if spectators are sitting on them.