If you live in a certain kind of urban area, you see it all the time: those new mixed-use buildings go up, and on the ground floor of practically every single one there’s a bank branch or two. And if you thought to yourself, “Why are there so freaking many bank branches opening in an era when all the young folk living in those buildings bank by phone?” you’re not alone. But it turns out there’s an easy reason that bank branches keep proliferating: customers are using ’em.

As Reuters points out, the banks don’t exactly like operating them. They cost money — lots of it.

A bank branch office costs between $2 and $4 million to get up and running, and another $200,000-$400,000 annually to operate. And sure, per year for a single location is just a tiny drop in the bucket for a bank, but multiply that out and it adds up fast.

Bank of America, for example, says on its website that it currently has about 4,700 “retail financial centers” in the U.S. Using Reuters’ cost estimate, that’s between $940 million and $1.88 billion in operations — a noticeable cost even for them. And that’s after closing roughly a quarter of their branches since 2009.

Investors, of course, want to see costs trimmed anywhere they can be. But this apparently isn’t one of those places. “Our customers still want to visit us,” a Wells Fargo exec told Reuters. “They’re still coming to our stores and our ATMs at pretty consistent rates.”

That’s not to say banks aren’t trying to get smarter about where they operate those locations. Chase bank, for example, has shut down about 5% of its locations — 265 total — since 2013, Reuters says, but executives say that doesn’t mean they should just fold them all.

“Often I will be asked why don’t we just accelerate closings. Why don’t we close 400 or 500 branches?” a JPMorganChase executive recently said to investors. “The answer is that customers won’t go there.”

So who’s using all those branches?

Well, you’d be right if you guessed older customers more than younger customers, for individual account-holders. Reuters looked at data from Chase and Wells Fargo showing that most customers go to branches several times per quarter, but that younger customers tend to visit less often than their elders.

Besides that, though, it’s small business owners who go in person. Sure, a trendy new salon or boutique might operate almost entirely off an iPad in the front running Square, but there are still plenty of small businesses that need to deposit cash or make change runs frequently. The proprietors of those small businesses may also want to negotiate business loans or talk money matters face-to-face.

“Proximity to their business is a very, very important factor to their bank selection and their continuing relationship with a bank,” a U.S. Bancorp executive told Reuters.

U.S. banks want to cut branches, but customers keep coming [Reuters]

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