Billionaire investor Warren Buffett says he’s not giving up his flip phone just yet, and he’s not the only one.

Buffett told CNBC Wednesday that he’s not interested in a new smartphone, even though Apple CEO Tim Cook has personally tried to convince him to join the iPhone revolution. Buffett — who recently predicted that cryptocurrencies will “come to a bad ending” — flashed a Samsung flip phone during an interview and said “the market is not yet saturated for iPhones.” Buffett’s Berkshire Hathaway is one of the top five shareholders in Apple.

Buffett isn’t alone. About 510 million flip phones were shipped worldwide in 2016, down from 543 million the year before. Smartphone shipments were triple that number, at about 1.47 billion in 2016, up from 1.44 billion in 2015. Best Buy BBY, -0.04% sells the Jitterbug prepaid flip phone for between $75 and $100, and Amazon AMZN, -1.78% has various models for as low as $25. Nostalgic fans of the Motorola MSI, -0.55% Razr flip phone can find refurbished ones on Amazon and eBay EBAY, -0.06% for $43 and up.

Jim Thatcher, an assistant professor of urban studies at the University of Washington, Tacoma, didn’t replace his smartphone when it broke. Instead, and only because his spouse and daughter’s school needed to be able to reach him in an emergency, he switched to a flip phone.

The switch has been therapeutic for Thatcher. He responds to emails more slowly and is less attuned to the news now. He also doesn’t check his phone if he gets bored and he’s more purposeful about how he uses his time. “I’m more focused on the immediate world around me, whether it’s observational or introspective,” he said. It also gives him more control over the data he shares, another big plus for him.

Flip phones are one of the original cell phones. They provide limited access to the internet, and the keyboard, known as “T9,” makes it more difficult for most people to type; to enter certain letters, you need to tap a number on the phone’s dial pad two or three times.

See also:What Donald Trump’s and Warren Buffett’s McDonald’s orders tell us about them

Apple AAPL, -3.17% launched the 10th-anniversay iPhone 8 and iPhone X in September 2017 with a price tag as high as $1,100 for the most expensive version of the latter. The company revolutionized the cell phone market when it came out with the first iPhone 10 years ago, effectively creating a multi-billion-dollar app market. Today, more than three-quarters of Americans use smartphones, according to the Pew Research Center, up from 35% when the center first conducted its smartphone ownership survey in 2011.

Not everybody wants a smartphone though, for the sake of simplicity — and, perhaps, sanity. Smartphones distract some people from getting their jobs and chores done, as well as from special moments with family and friends, thanks in part to all of the notifications popping up every few minutes and the easy accessibility to emails.

Jeff Bezos's vast wealth has reached uncharted territory

Even some very in-demand people use flip phones. Chris Pine, the “Star Trek” and “Wonder Woman” actor, uses a flip phone, he told Us Weekly magazine, as does country singer Dierks Bentley, People magazine reported. “I kind of like the simplifying down,” Pine told Us Weekly. “I don’t want to be connected so much.”

Many others have tweeted that they too wish they had flip phones, to “unplug” from their smartphones and connect with friends and loved ones in a more traditional way.

Smartphones may seem great for productivity and answering work emails on the go, but they actually hurt the average employees’ efficiency during the work day. Three-quarters of employers say two or more hours of the day are lost in productivity, partly due to texting, social media and email, and, of course, phones calls, according to a survey conducted for jobs site CareerBuilder. More than 80% of workers have a smartphone in view during the day.

“We’re not just attached, we’re addicted,” said Jim Roberts, a professor of marketing in the Hankamer School of Business at Baylor University in Waco, Texas, and author of “Shiny Objects: Why We Spend Money We Don’t Have in Search of Happiness We Can’t Buy.”

“We can’t resist the call of our smartphones,” he said. Some employers may be inspired to develop policies around phones to limit non-business-related usage, he said, especially considering the amount of time employees spend on their phones during the work week accounts for $15.5 billion in lost productivity.

Don’t miss:This is the gadget that could one day replace your smartphone

To cut down on the distraction problem, there are actually apps intended to boost productivity and limit smartphone time. They do so with varied methods and success. “Offtime” ($2.99 on Android and Apple’s iOS) monitors smartphone usage, but has received several one-star reviews on the iOS version. “ClearLock” (charges $1.67 for in-app products) for Android blocks apps, but has also received mixed reviews. “Forest” ($1.99 on iOS) attempts to thwart distractions using creativity: If a user opens another app after planting a virtual seed in Forest, the tree will ‘die.’

Feeling too attached to a smartphone but don’t want to switch to a flip phone? Stash it away in a drawer during meal times for starters, said Dale Archer, a psychiatrist and author of “Better Than Normal: How What Makes You Different Can Make You Exceptional.” “If you can’t do that, then maybe it is a severe addiction,” he said. Set aside time to live without your phone to have dinner with family and catch up with friends, Archer added.

See:Will a flip phone give my clients with iPhones the wrong impression?

Not all people are addicted to their phones, but there are certainly some who qualify as having an addiction and may not know it, Archer said. “Some will become severely addicted,” he added. “It will affect their productivity and relationships.”

A majority of students in 10 countries were distressed when they were without their phones for 24 hours, according to “The World Unplugged Project,” conducted at the University of Maryland, and most said they couldn’t go unplugged. Many said their smartphones were “essential to the way they construct and manage their friendships and social lives.”