In Spider-Man: Homecoming, we're introduced to Peter's new suit, given to him by Tony Stark, which has goggles over the eyes that can change shape and color. At the end of the movie,
when Spider-Man is fighting the Vulture in his homemade outfit, we see Peter's original goggles which also have this feature. That means that Tony thought they were useful enough to integrate into his own design.
So what do they do, aside from allowing Spider-Man to have more expressions? What are the tactical reasons why Mr. Stark decided to implement the moving goggles into Spider-Man's suit?