Oftentimes printing with accurate dimensions down to 10th of millimeter is not a big issue. For instance if you are printing a single piece object like a statue it doesn’t really matter if that’s 0.1 millimeter larger or smaller in Y axis or X axis or both. But sometimes the pieces that you are printing need to fit perfectly into each other or maybe need to be compatible with some non 3d-printed parts, like a 3d printed RC car that “I buit recently (maybe another article on that later).