If I'm understanding you, you are saying that who becomes the president does actually matter alot.

Every four years, the presidential election is on the same ballot as all the other local elections. You are advocating for voting, and you're not advocating for leaving the presidential vote blank on the ballot. If you're frustrated with having little power to make very important decisions, that is more than understandable.

However, you can only consider the effect of a presidential vote to be zero if you also consider the derivative in calculus to be zero. In terms of the presidential eletion, we aren't voting as individuals, we're voting as a state. Your vote matters.