Dowry giving is an ancient social practice. And centuries ago the dowry was meant as a means of protection for the bride from not only ill-treatment from the groom's family.......but also as financial security in the event the husband were to fall ill or die.
i think it was more of an inheritance issue. women move away after marriage to hubby dearest's hut, and were given their share of ancestral property's worth as dowry.
as for today, dowry will always lurk around in societies where women have poor economic and/or social worth.