Grassley offered the first accuser a hearing. She stalled and tried to run out the clock. The other accusers started their "remembering" around the same time.
Let's think about where we would be without the offer of a hearing. Ford would be on the news shows giving her "story" (not under oath). The others would also be me-tooing. The full Senate would stop their work for a two week debate over why Ford was not given a hearing, and the "pattern" that makes it more likely that what Ford is saying on the news shows is true.
Instead we have two allegations in play and offers to both for testimony. At least one gets a hearing. Only the committee can do hearings, the full senate cannot.
I don’t think there would be a delay if Grassley refused to entertain any accusations without supporting evidence. He could then blame Feinstein for holding on to the information so long that it would be impossible to evaluate any evidence, had their been any. Those are both good reasons to proceed to a vote, both in the committee and the full Senate.