In the 1st Century books were expensive. The bible was owned by the community of believers. Worship typically included regular reading of the scriptures, often according to a “lectionary” or reading plan.
This continues in churches who incorporate the lectionary in the worship service – usually these are more formal congregations.
Many of us have come to think of the bible as a personally owned book to be read privately. That is good. However it is also good to be where the book is read to the community.
First, because much of the Bible is written in a fashion that communicates well by clear reading out loud. (Much like how we were entertained around the camp fire recently with an out loud reading of Pride and Prejudice.) Books such as Psalms, which were sung, and Job which is poetic, as well as the histories which are narrative, all are served with a good reading well done.
Second, because we learn in community. When we all hear the text, we can all talk about it. Just as when everyone sees the latest episode of a TV show, we can talk about what has happened. Consider the great public reading of the book in Nehemiah 8.
Third, because this may be the only exposure to the word for those who can not, do not, or will not read on their own.
Fourth, it gives the text of scripture primacy against the star in the pulpit, at the podium, with the mike or on the screen.
Fifth, it gives an important work to “lay readers”, who more than the rest will concentrate on what they will read in order to read it well.