Imagine a situation where you are an owner of these business (from the picture on the right hand side.).
One day, you are opening a playland and therre also serve foods and beverages (F&B). Playland and F&B are separate business or sales.
During launching, you want them pay everything using phone. This is because you can send them promotion overtimes. So, instead of they just coming and go. With mobile app ready, you can invite them and send them the business promotion and highlights later.