It could be enough to eliminate some candidates forever. In the recent election, Dick Allen, Dave Parker, and Tommy John got a combined 34 votes. The maximum number of votes is 48; they don't report the number of votes for players who do not get at least 5 votes, but there with 14 possible votes unaccounted for, at least three of the remaining five players on the ballot were going to get fewer than five votes even if all 16 voters voted for the maximum. In every recent Eras Committee election, at least half of the candidates failed to muster five votes. It seems likely that candidates will get eliminated forever as this rule takes effect though it will take at least four to six years depending on which category a player is in. The players who failed to get five votes in the most recent election are safe of six years since they wouldn't be up again until 2027.
I think it does make it very hard for the PED guys to get in. Bonds, Clemens, and others not still on the BBWAA ballot could be on the Eras ballot this December. Bonds, Clemens, and Palmeiro all got fewer than five votes in December 2022. If they get fewer than five votes in 2025 and 2028, they could never be considered forever unless the rules were changed again. It's interesting to note that all of the six former Hall of Fame players on the committee had careers that overlapped with those candidates (and committee member former White Sox GM Ken Williams makes seven); yet some, probably most of them, didn't vote even for Bonds and Clemens.