Why do some stars lip-synch at concerts?

For a person who is good at singing and likes singing very much, singing is a pleasure, even if he is nervous before going on stage. It's even harder for you to let him lip-synch, because lip-synching is a test of acting. After all, there are few orthodox singers, and lip-synching is not easy. The live broadcast has changed a lot. If something goes wrong with the equipment and a big joke is made, the crime of lip-synching will be fixed forever. However, even the best singers sometimes lip-synch, including some singers, for some active or passive reasons, as mentioned in the above answer. I remember a famous Italy? The singer went to Japan to participate in the morning live program. Because I just got off the plane the day before and was still jet lagged, I was in a bad state and really couldn't sing. She proposed lip-synching, which was flatly rejected by the host. After negotiation, the singing part of the program was cancelled and turned into a pure interview. She invited to sing again the next day, and the singer accepted it gladly. However, for many artists with multi-habitat development, the public does not seem to treat them as singers. Their own banner is to pay attention to the effect of the stage and ignore singing in the hot dance. He may still be enjoying the performance, and his fans are fascinated and acquiesce in lip-synching.