Worst-case, they could hide what's happening on screen while reducing apparent image quality. Between sunlight during the day, and any lamps or ceiling lights in your room at night, you could be faced with annoying mirror-like reflections anytime you want to watch TV. Most modern TVs have a glossy screen that just loves to reflect even the tiniest amount of light. Reflections from the sun, or lights in your room, can be a distraction from an otherwise excellent 4K TV picture. A bright room can mean trouble for a TV screen with a glossy finish.
