Digital signage has so many applications. If you are a fast food restaurant it is an ideal way to display your full menu. At point of sale it is an invaluable tool to display special offers, push products that have a higher profit margin or simply inform your customers about important information such as travel or weather updates.
If you own a shop, you can visually advertise even when the doors are closed and the lights are off. There are a huge range of solutions from very cost effective to higher priced visually impacting displays. You can create whatever you want.