Every individual is unique and so is their destiny! In our society people have many beliefs / misconceptions about matching horoscope of Bride and Groom. Basically horoscope can predict upcoming events or at least the nature of events like joyful events or unpleasant events.
In my opinion matching horoscope before marriage is a must! The reason behind 'must' is very simple - every individual has their own cycles of happiness and sorrows. Therefore, it is extremely important that bride and groom should be in different stages of life cycle w.r.t. happiness and sorrows. So, that the couple can support each other during the difficult time. Matching horoscope is much beyond 'Gunmilan' - don't follow online software for matching horoscopes. Consult, your trusted astrologer and his opinion.