Direct Consumer Touch
One of the great things about custom apps for a business is the significant increase in customer touch afforded by always being just a swipe and tap away. Your website will rarely be so easy to access, no matter how accessible and available it is. This direct connection is very valuable and can be utilized in a variety of ways.
Everyone likes more income. Having your sales funnel in your customer's pocket is a great way to increase the likelihood that they will purchase from you.