The main advantage is compatible file structures… yes you can run an android app (virtually) on your windows system but the file it saves will not open up in the windows at your school without some type of converter. My windows phone can open the Onenote files I email home to myself, then edit/ save and email (or uplink to the cloud) ready to be opened again… this is particularly useful for me because the local schools tend to run seriously outdated operating systems that just don’t lend themselves to being tweaked.