Why brands must create their application?

This is a new age where people prefer to interact with brands and business through online platforms. And by creating an application the interactions are going to become a lot easier. One will be able to not only create android app that showcases their brand but they will be able to increase and retain their users as well as consumers. For that reason, it is best to create an application to allow users to buy and connect with the business. Do you think there are any other ways through which an application helps a brand?