A promotional video promotes a company's brand, products, and services to customers and prospects.  The approach does not always have to be direct or obvious.  Sometimes it's a soft sell and never mentions product or services.  However, their products and logos can be seen within the videos, but it's all done in a very subtle way.  Whether it's a video that celebrates an achievement, a special event, or a holiday wish.  The brand is being exposed to potential customers, but without directly asking customers to make a purchase.