[Huliwang]

seriously got this type of theory than how?

i only know some is due to $$$

Last time many old Chinese folks 50 or 60 years ago very superstitious wan. Sometimes when children sick see Chinese sinseh not get well so will go temple asked god aka sin for help. Sometimes tangkee wrote some yellow paper or hu and asked parent to burn and mix with water for the sick to drink. Some also advised parents to get god parents for the child for change of luck.....