I think the whole idea behind a reduced quorum is to not waste the witnesses' time. Often we have witnesses who come from across the country to see us, and for whatever reason, we may not have an exact quorum at 3:30. We have four witnesses who are at the table, members aren't here because they're tied up in other committees or in other business, and if the meeting doesn't start to receive their testimony, then it's wasted time for them.
I think the whole idea behind a reduced quorum is to allow the witnesses to read testimony into the record, while at the same time ensuring that no votes can take place and that no other debate or votes can take place. The whole idea behind this motion is just to allow the committee to receive testimony in the event that, for whatever reason, we don't have enough people here for an official quorum.