Mariology, or the study of Mary, is important in the life of the Church because it helps us remember how important the Mother of God is in the history of salvation. Mariology talks about the veneration (as opposed to the worship) that we give to Mary.
Many people, often of a generally-Protestant persuasion, do not see the veneration of Mary as important. Indeed some see it as offensive. The main reason for the perceived offence is because Mary is seen to detract from the divinity of her Son. He is the unique Mediator with the Father; He is the Saviour; He is the Redeemer. Why pray to anyone else?
The short answer to this question is that Our Lord asks us to have a relationship with His Mother. From the Cross, He tells St John, “Behold, this is your Mother”, after having told Mary to look after the Beloved disciple: “This is your son” (Jn 19,26-27). The Church has always believed that this is an encouragement for all of us to develop a relationship with Mary, conceived without sin.
From a purely psychological point of view it makes sense to venerate Mary. She is the Mother of God. Do we not trust mothers in general? Do not mothers listen to us, help us, direct us? Veneration of Mary is important because it helps us to remember that we are in a communion of trust and friendship not just with Christ, the unique Saviour of the world. He gives us the saints, of whom Mary is the greatest (being His Mother) to help us on our way. Just as we ask family and friends for help on life’s journey, so we seek the help of Mary and the saints to achieve our goal – the will of God and our own personal salvation.
Theologically it also makes sense to venerate Mary. Christ chose to be born of a woman “when the fullness of time had come” (Gal. 4, 4). If we are to be like Christ, then we too need to develop a relationship with him, as “sons in the Son”. His Mother brought Him into the world. In a spiritual sense she brings many more spiritual sons into the world: Christians who want to follow Jesus the Son of Mary.