What's the point of hanging clothes on the back of the chair when eating?

If you really want to pay attention, don't put it on the back of the chair. If you want to be particular, hang it on a hanger or give it to a waiter. High-end hotels have this service. If you put it on the back of the chair, you just don't want to pay attention. However, now some hotel lobbies will provide stool covers to cover your clothes to avoid oil pollution and theft. But this is what citizens should do.