The community has this tradition because it believes that although a child is born, the soul may not be here to stay. So the newborn is given a day name, and if a week has passed and the child is still unharmed by the earth, then they are given an actual name. The day name, however, is still just as important as a person's real name. Aside from this tradition, no one really knows where many of the other traditions came from. As with all the customs and beliefs around the world, there are not always explanations for the things we do. I am of Greek descent, and for Easter every year we have a tradition to paint eggs red and see which of them are the strongest. Two people will hit each other's egg, and whichever one doesn't break brings good luck for that individual. I could not tell you why we do this every year, but I can assure you we never fail to do it!
Out on the street, it is common to see people's day names used to advertise places, stores, and businesses. Spiritually, the concept of day names revolves around the idea that the earth must accept a newborn baby into life. It is the idea that although a baby is small and vulnerable, their soul must be strong.