The most prominently known use of robotics nowadays is in assembly lines to lower costs of simple, manual acts like the accompanying gifs. The left shows an easily replaceable assembly line for sandwiches, courtesy of The Simpsons. Pictured right is a car Assembly line. A robot's ability to act is benefitted by extreme precision and consistency, but it is unable to react properly to the same sort of stimuli a human can.
Other common uses are projects which are too dangerous for humans such as some construction sites, bomb disposal, and other such activities. Though more accurately classified as "Drones", they are nonetheless within the range of what most people consider to be a robot.