This post originally appeared on LinkedIn

High-tech banking in the ‘70s allowed customers to make deposits via pneumatic tubes without ever leaving their cars. It was the pinnacle of convenience at the time. You could make a deposit in five minutes without ever going inside.

Today, you don’t even need to be near a bank to deposit a check. Major banks now offer smartphone apps that let you simply take a picture of a check to deposit it. A deposit completed in seconds.

Customers love these new tools. Almost one-third of the 74,700 US consumers that Bain & Company surveyed for its latest global Customer Loyalty in Retail Banking report used smartphones or tablets for banking during the three months prior to the survey. That’s up from one-fifth of respondents in 2011.

But doesn’t automating interactions with customers and keeping them away from branches ultimately undermine customer loyalty?

On the contrary, mobile banking is more likely to increase a customer's likelihood to recommend his or her bank to other people than any other channel interaction, according to a follow-up survey with 5,200 of the survey’s US respondents. It’s a great way to delight the customer profitably, and an excellent example of what I like to call a “frugal wow.”

Routine interactions at the branch, by contrast, were far less likely to delight US customers and more likely to annoy them. If people didn’t want to stand on line to deposit checks in the 1970s, they certainly don’t want to do it today.

That’s good news for banks, not only because they can divert customers from higher-cost brick-and-mortar channels, but also because they can redesign those branches to handle moment-of-truth transactions that help build customer loyalty. This is particularly important for high-value affluent customers who may have more complicated accounts and need more personalized advice. Bain’s research shows banks don’t do a great job impressing these customers—in the United States, Canada, Australia, France and the UK, wealthy customers give the lowest loyalty scores. National US banks fare particularly poorly.

They’re missing out on a big opportunity. Converting an affluent customer from a detractor into a promoter has five times the economic value for a large bank compared to winning the loyalty of an average mass-market customer. Affluent customers who are promoters tend to buy more services than detractors, and they recommend the company to their friends and families, who are also likely to be affluent.

Of course, technology is no substitute for good overall service. But it’s an extremely powerful part of an “omnichannel” strategy that combines digital and in-person services to create a first-rate customer experience. These are the banks that customers (and investors) love.

What were you doing the last time you set foot in a bank branch? Was it for an important moment, like buying a house or opening an account for your child? Or was it for a task that felt like a waste of time? For many of us, the best thing banks can do to win our loyalty is to keep us away.