Because in the north, dealing with such things not only makes outsiders feel that the woman has a lot of dowry, but also improves her face. It can also solve some economic losses caused by bride price, or take dowry as the man's economic compensation.
On the contrary, on the issue of dowry, it seems that the south is not as tolerant as the north. I know some places where there is no dowry at all, or even very little dowry. Because southerners generally believe that a bride price is required to marry a daughter, and a dowry is dispensable. If you want a dowry, you will only give some cash or some other gifts, but these things are only symbolic and there is not much practical help in them.
In fact, in ancient times, no matter whether it was a bride price or a dowry, people would attach great importance to this matter, because it reflected the man's respect for the woman, and the dowry reflected the woman's attention to her daughter, so it would be particularly rich when preparing the dowry, so that the daughter could be married to the south and the man would not look down on his home. To a large extent, northerners have followed this custom, while southerners seem to have little or no inheritance of this custom, so on the issue of dowry, the south is dispensable.