Advantages of apps over websites:

• Gobbling data: an app does not get its request blocked as a website does.
• Making money: This one applies more to indie developers than to big companies but I'm sure people are more willing to pay for an app than access to a website.
• people want app: Think about that for a second: people want to download an app to track deliveries of their white goods, something which most people order at most once a year.