CebuCity,

It looks like the snapshots do take up some space on your hard drive. However, you should know that you can't restore the entire system from the internal hard drive it the system crashes. The reason for this is that if you do have a hard drive failure, it's often mechanical in nature. If you can't access your regular files on the hard drive because it doesn't work anymore, how do you expect to access the "backup" files on it? The answer is, you can't, because the hard drive is broken. The whole point of a backup is to have a completely separate hard drive with all the data on it in case the one in you computer fails.