Bank of America Corp. officially unveiled its renovated local flagship branch in downtown Boston this week.

Glass walls have replaced stately wood. The bank manager now wears a discreet earpiece as he greets you at the front entrance, like a host at a restaurant. A row of computer tablets sit perched on a long bar, ready to show customers how to pay their bills online. And tellers, once the centerpiece of any bank branch, are now in the basement.

Bank of America is updating 1,500 of its branches across the country, and 53 in New England, in the next two years to mimic the Federal Street branch.

The question is: why?

At a time when millions do their banking at ATMs, on their phones, or online, why would Bank of America want to spend money revamping branches that most of their customers never visit?

The answer can be found in the updated downtown branch. The ground floor has been largely turned over to investment advisers from Merrill Lynch — which Bank of America owns — as the bank increasingly turns its focus to those kind of services, rather than check cashing.

Nationwide, traffic into bank branches has dropped significantly in recent years, as one in five check deposits are now made by customers over their smartphones. In fact, the volume of transactions via smartphones and other mobile devices is the equivalent of what 1,000 branches collectively handle through customer visits, said Dean Athanasia, co-head of consumer banking for Charlotte, N.C.-based, Bank of America.

The bank has shuttered about 1,300 branches since 2010, bringing its current total to about 4,600 nationwide.

Still, banks aren’t ready to give up on branches entirely.

“We’ll always have them,’’ Athanasia said. “The function will be different. People still want to come in for advice.’’

But branches will no longer be designed to focus on traditional interactions with customers, such as cashing checks, providing account balances, and depositing money. Customers are now more likely to come to a branch for very specific and more complex transactions, such as small business loans, mortgages, and setting up college funds, Athanasia said.

And Bank of America still needs a place to sell customers those products.

The bank has put its investment services front-and-center, with much of its main floor space dedicated to its Merrill Lynch arm, pitching customers on wealth management and retirement planning behind glass offices. In the first three months of this year, Bank of America’s wealth and investment management arm, which includes Merrill Lynch, earned a profit of $770 million, a 4 percent increase over the same period last year. That helped the bank post a $4.9 billion profit, a 40 percent jump.

And Bank of America isn’t alone in reimagining its branches.

Some banks have taken their cue from Apple Inc. stores and feature plenty of screens and white countertops. Others have installed coffee bars and community centers.

Providence-based Citizens Financial Group Inc. has renovated 35 of its branches, including eight in the Boston area, and plans to redesign another 45 by the end of the year. The overall space has shrunk, with fewer teller counters and more private meeting rooms and offices for one-on-one conversations with customers.

“We are shifting from a transactional organization to one that is based on building relationships and designed to help our customers gain access to advice that can help their overall financial health,’’ said Lauren DiGeronimo, a spokeswoman for Citizens.

Nationwide, despite all the chatter about the rise of technology and the death of the bank branch, banks in general have been reluctant to close what may be the best advertising vehicles they have.

Since the 2008 financial crisis, the number of branches has dropped only slightly, by about 3 percent. The United States had nearly 80,820 branches at the end of 2016, down from a peak of 83,600 in 2012, according to Keefe, Bruyette & Woods Inc., a New York investment firm.

That rate of closures is likely to remain steady, as interest rates rise and banks make more money off loans, boosting the bottom line and easing the pressure to cut costs and close branches, Keefe, Bruyette & Woods predicts.

Another factor: Traditional banks don’t see their online-focused competitors performing that much better.

Capital One, which directs most of its customers to online banking, has a few financial centers tucked into coffee shops, including eight in the Boston area. But it has only grown its share of deposits nationwide by about 11 percent since 2010. That compares with the more than 30 percent growth that Bank of America has seen in its deposits over the same period, according to the consumer website WalletHub.

Hoai-Luu Q. Nguyen, an assistant business professor at the University of California at Berkeley, said she hasn’t walked into a bank branch in a decade, but for some consumers, particularly small businesses, they are crucial.

Nguyen’s research has found that access to business loans for small firms declines sharply and persists for several years after a branch closes, even if there’s another one around the corner, because so much of that lending depends on relationships built over time.

Lending to small-business owners, which can be risky, is based on an individual banker’s understanding of the community and knowledge of the borrower, and not simply credit scores, Nguyen said.

“We think we’re in a world where online and mobile banking is very prevalent, but there are certain parts of the economy where the local connection is really important,’’ she said. “The local presence of a bank is still important.’’

Deirdre Fernandes can be reached at deirdre.fernandes@globe.com. Follow her on Twitter @fernandesglobe.