TikTok is an "the ads are the content" type place, think Zach King (sp?), he makes clever videos as adverts but they also comprise his channels content on TikTok. If TikTok can/do monetise that usage of their system then they can get a payout from advertising.
Or they can get TikTok to the height of popularity and slowly kill it by adding more and more ads ... the 'YouTube Way', one might say.
They'll also need their own copyright detection system when lawsuits start coming their way. Then we'll have come full circle.