Inevitably, we have developed a need for automation, despite the fact that humanity was able to live without it for most of history.
Today, much of the need for robots arises from the fact that humans have this need to learn more. And, in many cases, humanity wants to learn more about places we cannot yet explore on our own, i.e. the inside of a volcano or a hurricane, the surface of Mars, deep under the oceans, or even the inside of a person. We cannot get there ourselves, so we send in robots while it is yet too expensive and/or too dangerous to get there ourselves.