We are not talking about the dramatization of a biblical story or event - of dividing the Scripture text into separate speaking parts and a narrator. We are using "dramatic" in a more generic sense. All drama involves some kind of change, where something is markedly different between the beginning and ending of a script or text. Most often this results from the tension or conflict that is being played out between opposing or differing forces.
A choral reading can serve to highlight the tensions that are at work within any given passage from Scripture. There may be personal, moral or ideological tensions between characters within a story. Or there may be differences the voices and imagery of tradition and the reality of current practices. These tensions are brought to the foreground and enlivened in a dramatic reading through the use of multiple readers. Each reader can embody a different voice or perspective.
Some passages of Scripture have become all too familiar so that they have lost a lot of their meaning and import for us. In order to disturb this familiarity, dramatic readings often make use of juxtaposition to heighten the sense of contrast or tension. Old is set against new, right against wrong, weak against strong - so each can be seen more plainly for what it is.
Choral readings are not an add-on inserted to enliven the regular worship of a congregation. They need to be thoughtfully integrated into the flow and dynamic whole of the service.
Readings should not stand out or disrupt the flow of the worship. They are part of God speaking to his people in the dialogue that is the liturgy.
A well-constructed worship service will take the main theme and weave it throughout the various elements of the the service to engender an overall impact that is cohesive. The theme is most often taken from Scripture. It is the source from which the rest of the service flows.
Choral readings serve best to enhance and enrich the hearing and reception of Scripture in the liturgy, wherever that takes place. Quite often it is used as an expansion or amplification of the "Reading of the Word" that takes place before the sermon. (If the readings are taken from the Lectionary, the dramatic reading can thematically link together the Old Testament, Psalms and New Testament passages.)
Dramatic readings also serve admirably in other parts of the liturgy: