There are several good reasons. If you need to work on homework assignments that needs Linux, the ability to take Linux with you means you can continue to work even when you are not at school, and have no access to a remote server.
The ability to take Linux with you also means that you can run your own OS, configured the way you like it, along with all the data and application, anywhere you go! There is no need to worry about whether a certain application is installed on a machine that you normally do not use.