You have a right to a sense of meaning in your work. That sense of meaning can be hindered by things such as: a wrong fit with the work you are doing, values not being honored, a dysfunctional workplace or a lack of resources or skills to do your job.
When you find yourself asking, “What’s the use?” take a look at the source of your frustration. Once you discover it, do what you can to remedy the situation. In that way, you assure that your work fulfills you. It’s better for you and for the world.