A backup is a copy of a site that's kept on a separate web server and could be restored if something goes wrong with the live website - an unsuccessful script update, an unintentional deletion of some file or of your whole database, and so forth. Restoring the Internet site the way it was shall remove or reduce the damage the issue may have caused, that's by all means a much better option than having to reconstruct your whole website from scratch. Even though you can download a copy of your content on your personal computer, keeping a backup is a functionality that nearly all web hosting providers incorporate as part of their plans. You have to take a look at how often they do that, though, because some companies create a backup just once every few days, which might be far from enough for a booking website or an e-commerce portal where the data is updated every single day. You should also see how fast and easy a backup could be restored, which can be crucial if some problem appears on your website.