God uses whatever is available, like you and me when we're available. He doesn't create Saints out of thin air, He creates them out of flesh-and-blood, and normal people like you and me who love the Lord and will let Him use us.
Most of the greatest saints the World has ever known were little people who just did what they thought should be done--whether others ever heard about it or not! But they were always there when they were needed, always willing to see the need and respond. If we have real love for the Lord and others, we'll do whatever needs to be done! It all depends upon our yieldedness and willingness to be made willing. It depends on our humility, which is synonymous with love, which is the only thing that can make us willing to go anywhere, anytime, to do anything, for anybody, and be nobody, to please Him and help everybody! (Rom.12:1; Phi.2:3,4)