I believe theres a lot of pressure among Senators to get the new SC justice confirmed before Election Day. Many of them probably figure they dont want voters to feel that their votes can somehow influence the results of the confirmation process. A quick confirmation effectively removes the SC nomination as an election issue entirely. The GOP may also figure that a quick confirmation will solidify their support even among many NeverTrumpers ... and will completely demoralize the Democrat base.
Never Trumpers would prefer that Biden choose Ginsburg's replacement.