Any life is insignificant.
But the people play their parts, and play them with gusto, because they believe that their lives are significant.
Looking through the microscope at microorganisms, then the ocean with the microorganisms floating on the surface that extends to a far horizon in every direction, and travel over the ocean, and more, more microorganisms, and then the generations, the generations long dead of the microorganisms, and a person is but one microorganism, insignificant on a scale incomprehensible to the human mind.