One of the arguments I often hear from people who are trying to use linux for the first time is that they are not sure if they can switch back to their original choice of OS (usually windows), if they are not satisfied with their experience with linux. These are usually the people who are not as tech savy or previously had bad experience while trying to install linux which resulted in destroying their windows installation. With each iteration of windows OS Microsoft has made it less friendlier for linux to be installed along with windows.