Why are visualisations useful for communicating information?

There are several reasons that visualisations are useful for communicating information. One reason is that the messages we are trying to convey can often be based on large amounts of data. In this case, visualisations can provide a useful way of summarising the data to present significant patterns in an easily consumable manner. Another reason worth highlighting is that the choice of the right visualisations can direct the viewer to a conclusion, for example a heat-map might concentrate the viewers attention to a particular set of data points.