Consider the recent example of John Cena, an actor in the "Fast and Furious" franchise, apologizing to China for calling Taiwan a country. Is that apology good, bad, or irrelevant? Probably irrelevant by itself, I'd say.
But what about China's ability to coerce John Cena into making that apology? This is more akin to the problem you might see on TikTok. Influential people that others look up to parroting Chinese propaganda, wittingly or unwittingly.
It doesn't require much imagination to see the problem. If China secretly coerced 10 famous actors to say, "the US should leave Taiwan to China," and those videos had >100 million views in the US, that could be a very successful influence operation. TikTok could be a means of distribution for that kind of thing.