Goggles or face shields should be worn when carrying out jobs which require close face-to-face contact, such as those working in a restaurant or a salon.
Face shields are good at protecting you from large droplets that may come into contact with your mouth, eyes and nose, especially when talking to someone who is not wearing a mask. However, they are not as effective at protecting you from smaller droplets that contain SARS-CoV-2 viral particles, since they can go around the shield. Whenever wearing a face-shield, it is always best to pair it with a mask.
Eye protection also protects us from (unconsciously) touching our eyes with unclean fingers.