What is the advantage of using telescopes set up in an array

Let us say that I have three or more optical telescopes networkes together and evenly spaced out along a radius of one kilometer. If I pointed all of the telescopes towards the same object in the sky, would that amount to looking at the observed object with a two-kilometer telescope or does this only work when measuring radio waves? In other words, is there any advantage to placing optical telescopes in a large array or not? Wouldn't the image show more detail with each telescope added? Wouldn't it be easier to determine the speed, rotation and direction of solar bodies such as asteroids? The only telescope arrays that I know of has to do with the measurement of radio waves.