The election rests on the "undecided voter", which is a person I have a really hard time understanding at this point. So yeah, what effect will this have? Damned if I know.
If a party can’t get its voters to come out - especially reluctant voters, that can make a big difference. If you are a Democrat but aren’t that keen on Biden and you think he’ll win your area anyway, you might lot bother with the half hour trip, and that might swing the election.