|Well there are many advantages to online storage services.|
1. They are off-site so if your house gets robbed or burns down, you still have your data.
2. USB devices are just as susceptible to going bad as the built in hard drive.
3. You can access this data anywhere in the world.
4. You don't have to hassle with keeping your data offsite if that's what you choose to do.
5. 128 bit encryption while transferring and 448 bit blowfish encryption on the server so it would be pretty hard for someone to access your data.
6. It's all backed up automatically in the background so you don't have to worry about scheduling your backups.