First, it creates an explicit link between two things that otherwise might not have been connected. Think about how the following statements relate to each other, even though there is no contrasting conjunction, e.g. ‘but’ or ‘however’. ‘The introduction of your paper was well written; the conclusions were lacking in support’. Both are treating the same subject, and at face value there is a minimal amount of contrast present in the content. Adding a connector like ‘but’ at the beginning of the second