You need to protect the most important information that is on your computer hard drive. You can back it up in a variety of ways locally and keep those copies nearby in case your computer goes dead, but what about a disaster that could destroy not only the computer itself but all those physical back ups you made? Fires and floods, tornadoes and hurricanes all can wipe out the data you so carefully tried to preserve. This is a huge reason to always rely on online file backup to have a remote copy of those irreplaceable files in a different location.