Here are the main purposes of digital signage accordingly to Wikipedia
Information – examples include flight information in airports and wait-times for the next train
Enhanced customer experience – examples include digital signage in restaurant waiting areas to reduce perceived wait-time and recipe demonstrations in food stores
Environment enhancing - such as using digital signage to increase the customer experience with the building itself, examples of this are where digital signage panels are used on the floor and react to how and when an individual moves over them
Influencing customer behavior – examples include post office digital signage that directs patrons waiting in line to automated stamp machines and retail digital signage designed to direct customers to different areas of the store, increasing the time spent on the store premises (dwell time)
Advertising related to the location to uplift sales – examples include in-store promotions in a retail establishment
Digital signage can also be used in a corporate environment, for example by disseminating information throughout a company via screens in reception areas and canteens.