Notice how this sort of disappeared (from the news cycle) with no follow-up?
I guess he didn't actually have anything more to say in the SCIF?
The dog-and-pony show fulfilled its objectives for all involved.
For the UFO enthusiasts, it provided on-record, almost-but-not-quite firsthand testimony that the government possesses recovered alien technology. They literally don't care that the actual evidence—which was ever only alluded to and never produced—is still secret. They have it on "highly credible testimony" that it exists and that skeptics will never get to see and debunk it.
The UFO grifters get a shot in the arm by being able to say that Congress took them seriously, so please keep attending their panels and conventions and paying top dollar for autographs and appearances. The last thing any of these actors want is for evidence to actually be presented (even under seal), examined, and verified. They don't want evidence of aliens to be widely accepted by the mainstream because their entire existence is predicated on their being a minority crusading against the evil Establishment. As soon as it's generally accepted that aliens have visited Earth, they lose their special status among their followers. They become just another voice in the majority and therefore not special anymore. Then they have to go out and get real jobs.
The few Congresspersons who have a stake in UFOs get the semblance of credibility. Without much exception, any member of Congress can hold hearings on any subject for any reason. "Investigations" by Congress as the fact-finding component of its legislative mission has grown to encompass quite a lot of time wasting. As we first pointed out, some members of Congress have wealthy donors who believe in UFOs, and in return these Congress members have thrown them lucrative no-bid contracts to "study" or otherwise capitalize on the phenomenon.
"Highly credible witnesses" testifying under oath that they know of people who have seen, handled, and worked on recovered alien technology helps silence those who would criticize this grift. Again, it doesn't matter that the evidence almost certainly does not actually exist and dubious that claims that it does—but is too highly classified to present—will almost certainly go uninvestigated, unverified, and unpunished. The Congresspersons involved can say to their critics, "See, we have testimonial evidence that alien artifacts exist, but the rest is classified above your pay grades."
There are a number of SCIFs in the Capitol complex. It would not have been even the slightest bit inconvenient for a select committee to announce it is going into executive session in a SCIF and receive classified testimony right then and there.