This article orginally appeared in CEO Forum.

Commonwealth Bank of Australia (CBA) has enjoyed a brisk uptake by customers of its mobile app that includes tools such as a “property guide”, which maps past home sales history, current listings and recent sales to a real-world view through a smartphone’s camera of 95% of homes in the country. What does that do for the business? First, smart-phone-toting customers tend to recommend their bank more than customers who don’t yet bank through mobile devices. Second, mobile usage also tends to reduce the number of branch visits, which can lead to lower costs.

Mobile banking is finally coming into its own in Australia and other countries. Some 27% of Australian consumers that Bain & Company surveyed recently used their smart phones or tables from some type of banking interaction during the previous three months. That’s slightly below the global average, though it is higher among more affluent consumers and those in the 25- to 35-year age group. And online usage in Australia stands much higher, at 84%.

The relative importance of mobile, online, and other channels emerged from Bain’s new survey of 8,500 retail bank account holders in Australia plus customers in 13 other countries across Asia, the Americas and Europe. Our survey finds that in many countries, mobile and online channels are delighting consumers. People love advanced features such as remote bill-paying . They also value the convenience of mobile devices for straightforward tasks such as checking their account balance.

Australian banks are innovating through digital channels with a vengeance. CBA, for instance, offers a web portal that makes it easier for customers to buy and finance a used car. Westpac recently introduced an application for the Apple iPad that allows customers to drag and drop their accounts to transfer funds or make payments. Westpac expects the number of customers using mobile banking to more than triple over the next five years. ANZ recently launched ANZ FastPay, the first Australian banking app to process same-day credit and debit card transactions using an iPhone or iPad. And National Australia Bank recently started a “social media command centre” to allow the bank to respond to customer inquiries via social media platforms more efficiently.

For retail bankers battling to retain customers and sell them more financial products, digital channels have become a powerful means of building loyalty—when these channels emphasize the right features and transactions, and when they dovetail tightly with phone centres and other ways that banks touch their customers.

Banks shouldn’t assume they can build out mobile platforms and loyal customers will follow, however. Mobile banking usage increases with income, our survey finds, yet the most affluent, high-value customers in Australia give their banks lower loyalty scores than do other income segments. Wealthy customers are more demanding. They tend to look for premium service and tailored, expert advice through personal banking relationships, not just convenient digital channels.

Why do affluent customers matter so much? Moving affluent or mass-affluent customers from being "detractors" or "passives" to being "promoters" of the bank is worth roughly five times the economic value of turning mass-market customers into promoters, we estimate. Affluent Australian promoters own more products at a bank than do affluent detractors, and they tend to recommend their bank to affluent friends and family.

The two major themes of the survey findings—a surge in mobile banking and the tepid loyalty scores of affluent customers—point to a logical way forward. If Australian banks can take out costs in the processes that handle routine transactions, they will be able to serve mass segments more profitably and invest disproportionately in high-margin services for the affluent.

Digital banking reduces branch visits, setting the stage for major branch redesign – and thereby for serving a mass market efficiently. Relative to other countries surveyed, Australia has the lowest number of branch visits per year, on average, suggesting that Australia may be ahead of the curve in migrating customers online. Once customers turn to mobile banking, many of them report that they make fewer visits to a branch. However, some 67% of Australian customers are still using the branch for routine tasks.

Branches will not disappear, but their role will shift through lighter but sturdier formats. A few examples in other countries show the range of possibilities.

Citibank is piloting tech-intensive branches at high-traffic locations in Singapore, Hong Kong and Japan that rely on touch-screen walls, tablets and teleconference facilities. The point is to raise customer engagement with advisory services, while providing faster self-service for routine transactions through Internet kiosks. Fortis and easyCredit in Germany operate self-service terminals where customers can fill out the first stage of a credit application or pick up product packages to complete online at home.

Most customers will embrace such formats if the self-service channels are intuitive and convenient. The challenge is to integrate disparate channels into a seamless “omnichannel” experience. Solid execution of the details will be critical. Does the bank prepopulate certain fields on application forms with customer data it already has? Do branch employees actively inform every walk-in customer about mobile applications? Does the core IT system provide a single master view of the customer?

Leading banks in other countries have already begun their network redesign. Australian banks should accelerate the process now before outside disruptors do. Waiting to act until the branches are drained of all routine transactions will be too late.