(I ask out of genuine naivety to US political research/processes/inquiries)
My main reservation for not buying the outcome of a house panel is qualification. These are just elected politicians. How are any of us supposed to trust that they can grok science? The whole thing would have to come at ELI5 level simplicity.
If it was started on more even grounds and based on testimony by domain experts with traceable evidence, etc. it’s a lot more reliable. That doesn’t mean it’s perfect - e.g. past testimony on Alzheimer’s disease would have reflected the scientific consensus skewed by Eliezer Masliah’s fraud – but it usually won’t be out of line with what experts in the field agree.
This is why the gold standard government reports are prepared not in the legislature but in dedicated agencies where the people working on them are not political appointees. If NIH or the EPA releases a report, it’ll often be peer-reviewed and will list the people who worked on it and their qualifications – usually advanced degrees in the subject and often a research career prior to becoming a civil servant.
The higher the stakes the greater the scrutiny.
As a concrete example, Republicans made vaccination a highly contentious political litmus test. A lot of doctors are Republicans, but that lead to most of them staying quiet or making very moderate positions – the few exceptions being noteworthy because they represented such a small minority of their peers.