TikTok is ostensibly a commercial product meant to earn revenue that offset costs, and those costs are tremendous.

Meanwhile, the ban will make it impossible for them to (a) enter into trade relationships with the advertisers and other partners that bring in revenu, and (b) share that revenue with monetized users.

Continuing to run it at scale as a website without ads or monetization payouts (and without any legal protections) would pretty well blow the cover of it being a legitimate international business.