Yes, voting matters, because sometimes elections are very close. Making sure good candidates take office is very important, because corrupt leaders can create large problems, and destroy economies. A good leader is critical to the function of society. Citizens should take this responsibility seriously, and make sure to vote after researching candidates.
I think voting matters to a certain extent however what matters more is there voting options. I think if voting were to stop there would be a huge uproar so I do not think I would say that it does not matter, it might not be as effective all the time as we would like it to be but nonetheless it matters.
Listen, we have no influence over who runs the world. The democratic system is a façade. The interests of the powerful are always adhered to regardless of your vote. No matter who you elect ultimately you are not the one who decides the leaders of this society. You merely elect puppets of the system.