Your vote always matters. Your vote gets tallied up along with all of the other votes, each of which individually have exactly equal weight compared to your own vote.
By extension: Any suggestion to the contrary is delusional.
The vote that is never cast is absolutely worthless. You're correct.
(I vote every single time unless my ballot would simply be empty. I'd like to say "I'll see you at the polls!" but that is seemingly a lost cause -- it's apparent that only one of us has any chance at all of imparting any change at this level, and that this person is not you.
But you do you. The folks who aren't nihilists will do what we can to steer the ship without your help.)
By extension: Any suggestion to the contrary is delusional.