I wonder what the answer for this is? On one hand, you're absolutely right, these events are opportunities for grandstanding.
On the other hand, the meetings of the government should be open and transparent by default.
On the other hand, the meetings of the government should be open and transparent by default.
Don't rely on politicians to do direct questioning of witnesses. Politicians have the wrong incentives, and generally lack the skills, to do anything other than grandstand in public meetings.
Legal fact-finding, including the questioning of witnesses, should be done by lawyers and subject matter experts.