No rational person believes that their vote is decisive but then no intelligent person in a democracy let's that knowledge keep them from voting. That's how we got the election results in OH, as well as in the '20 presidential election, the '22 midterms and runoff in GA, and the numerous pro-freedom of choice votes in red states.
Democratic elections are essentially an act of faith, a leap of faith, expressed as the will of a majority of voters.
Trump won in '16 in defiance of the will of a majority of votes; lost, bigly, in '20 from an even greater expression of the will of the majority of voters.