Is this an issue of national Security? Who has what information? Who is housing what artifacts? What funds are used to pay for these projects? Who has committed crimes to hide this information?
All those questions weren't asked because anyone expected Grush, Fravour or Graves to tell them: Yeah I've got a UFO in my garage. In fact all witnesses answered all those questions before. This had one specific goal: Get this into congressional testimony, under oath, from credible witnesses and thus give congress the means, information and constitutional duty to investigate further.
And for all those sceptics out there: this is unusually bipartisan and seeing Gaetz and AOC both laserfocused on investigating government misuse of money on such a historically fringe subject is most interesting.