(Reuters) - TikTok is entering its final hours in the U.S. ahead of a potential ban effective on Sunday, prompting howls of protest from devoted users of the beloved video-streaming app.

Chelsea Rossi could not be happier.

The part-time real estate agent from Albany, New York, said she spends a minimum of two hours on the app each day flipping through short videos covering anything from beauty tips to recipes.

"It's horrific," said the 23-year-old. "Honestly, I am happy about the ban. I feel like I don't remember what life was like before TikTok."

Owned by China's ByteDance, the app faces a complete U.S. ban on Sunday unless it finds a non-Chinese buyer. The planned shutdown stems from an April law signed by President Joe Biden that will bar new downloads on Apple ( AAPL ) or Google app stores and prohibit companies from providing services that enable the app.

The U.S. Supreme Court refused to rescue TikTok on Friday from the law in a major blow to a platform used by nearly half of Americans.

Lawmakers allege it is a surveillance and propaganda machine camouflaged in banal dancing, prank and cooking videos served daily to some 170 million U.S. users. TikTok has repeatedly denied this.

Although some key U.S. officials are attempting to delay a shutdown, some users are hopeful the highly addictive app disappears forever.

Jennifer Whims, of Snohomish County, Washington, said she has uninstalled the app multiple times since discovering it years ago - only to reinstall it days later.

"It's become too much of a part of my life," said Whims, 32, whose daily diet of five hours of TikTok videos includes tarot readings and self-help instruction. "I'll be relieved when the ban is in effect."

The app has grown into a cultural phenomenon, minting a smattering of influencers and new celebrities whose reach has proven irresistible to advertisers paying them to peddle products such as Momofuku ramen noodles and Birkenstock knockoff sandals in TikTok's online store. 

Musicians such as Lil Nas X have catapulted to fame in part because of TikTok's reach, while book enthusiasts on the app have lifted authors such as Colleen Hoover to the top of bestseller lists.

ALGORITHM MAKES APP ADDICTIVE

TikTok's secret sauce is its algorithm, which adapts to users' behavior, showing more of some videos and less of others based on factors such as how long they watch and whether they comment or click a digital heart to "like" content. Meta's Facebook and Google's YouTube, among others, are also designed to enthrall users, keeping them pinned to their phones. 

Yet the TikTok algorithm makes the app particularly addictive, users say, rendering it nearly impossible to watch just one or a handful of videos in a single sitting. And the more one- to three-minute videos users consume, the better the algorithm adapts to make it even more irresistible. 

"There's definitely a dark side to it," said Andrew Coleburn, 30, a software engineer in New York City. "I can almost feel it decreasing my attention span."

Research shows TikTok is particularly well-designed to encourage overuse and court documents suggest TikTok knew it could become habit-forming. Thirteen states and the District of Columbia sued the company, pointing in part to its addictive qualities. The company has pushed back against those allegations and notes it has user controls, particularly for teens. 

Coleburn and others say they prefer TikTok to other video-streaming sites such as Instagram Reels.

Like Whims, he has taken measures to curb his use, including setting a one-hour daily time limit on using TikTok on his phone. "I blow past that all the time," Coleburn said.   

The potential ban has sparked free-speech concerns and worries about government overreach. President-elect Donald Trump and a growing list of U.S. officials have vowed to intervene to spare the app from dissolution in the U.S. but it is unclear whether Trump has the authority to do so.

Interior designer Abigail Green of Columbus, Ohio, said she will be happy if a ban gets her off TikTok. At her peak usage, she clocked four hours on the app each day and purchased a lip stain she had seen touted on TikTok, though it did not last all day as promised. 

Green, 23, who has posted some of her own content on TikTok, such as displays of her thrift-store purchases, said the app's addictive qualities were dangerous because she could "scroll for hours and hours." 

"I had to delete the app a few times to detox," said Green, who likens the demise of TikTok as akin to taking away a smoker's pack of cigarettes.

With his newfound time following TikTok's domestic shutdown, Coleburn plans to read more books. "I've found some new books to read recently that I never would have otherwise," he said. 

Where? On TikTok.