The main purpose of using public spoons and chopsticks is to reduce the chance of indirect oral contact and the risk of indirect oral transmission, prevent and reduce the spread of cross-infection and food-borne diseases, and cut off the "oral" transmission route of infectious diseases. If you don't use public chopsticks, the bacteria carried by your mouth and nose will spread to dishes through chopsticks, which will also lead to cross-contamination of bacteria carried by different dishes.
There are two advantages to using the public spoon and chopsticks: 1, cleanliness and hygiene, and disease prevention; 2, reduce waste, civilized catering.