I didn't watch the hearing myself, but at least some of the press has presented it as
Chew often stalled, repeated a set of scripted talking points, and avoided giving direct answers. He maintained composure throughout, yet his boilerplate commentary gave the impression that his bosses at ByteDance had forbidden him from saying anything of much substance.
[...] Chew repeatedly declined to say whether TikTok was a Chinese company or whether many of its executives were C.C.P. members.
So that can be another reason to have the hearings, i.e. someone like me who doesn't have time to watch them, then reads a press report that says that TikTok does seem to have something to hide, as evidenced in the hearings.
At times, his responses bordered on unintentionally comedic. When the Republican congressman Neal Dunn, of Florida, asked if the Chinese Communist Party had compelled ByteDance to spy on American journalists, as Forbes reported last year, Chew at first said no, and then, when the question was repeated, “I don’t think ‘spying’ is the right way to describe it.” His constant refrain, particularly regarding details of the platform’s technology, was a punting “I’ll have to get back to you on that.”
I.e, what one comment [to the other answer] said that even if it was the Congresspersons who looked stupid 99% of that hearing, if it yielded one juicy bit like the one above, perhaps they thought it was worth it.
And other Qs, like the one about Uyghurs, were clearly intended to put Chew in a catch-22 situation, so he didn't really answer them, except with more evasion (even though that Uyghurs Q was repeated 4 times). These were definitely intended to cast doubt on his opening statement that "ByteDance is not an agent of China", as in: look he says that, but he toes the CCP line on a lot of topics. (And of course, the Congressperson who asked that then posted the segment on her Twitter account, i.e. it also ties in with Congressperson self-promotion.)
BTW, CGTN's print coverage instead emphasized that Congresspersons "were focused on being xenophobic". And their TV selection of the footage snipped to some one minute when one Congressman insisted on a yes/no answer about some algorithms. The rest was studio commentary that Chew was "verbally brutalized" by "xenophobic behavior". The thing about technical [in]competence it is that's hard to convey to a broad audience. So CGTN seemingly didn't even try that angle much; the studio commentary on that segment instead focused on how unreasonable the yes/no approach was to a complex issue. (There's a longer CGTN segment where there's also some footage from the hearing, but the audio from the hearing was entirely replaced with studio commentary!) Anyhow, few in the US watch CGTN or other Chinese media. And the (5 hours) hearings are too long for most people to watch them in their free time, so they'd rely on some summary.