"The benefit of descendants" means: it will bring benefits to future generations, or make descendants prosperous.
This sentence mostly comes from fortune-telling texts. For example: If the six relatives are harmonious, it will bring benefits to children, but it is unlucky for women. If used, it will ruin the husband's luck.
Fortune telling usually refers to eight-character fortune telling or four-pillar prediction. Luo Lihua, a master of Yi Xue, said: It is a traditional Chinese prediction method for the changing laws of life movements. The year, month, day, and hour of a person's birth are calculated by arranging them into eight characters (called "eight characters") according to the heavenly stems and earthly branches. Using the five elements of the stems and branches to predict a person's destiny is a method of using personal information, such as the lines on the face and hands, birth horoscopes, name strokes and other combined magic to predict or judge destiny, good or bad, and seek guidance. Behavior is also called fortune telling. Learned fortune tellers associate fortune telling with the Book of Changes, one of the Five Classics. In fact, "The Book of Changes" itself is considered by some people to be the earliest book of divination, but these are often difficult to verify scientifically, so some people think it is superstitious.