A backup is a copy of a site which is kept on another web server and could be restored if a problem occurs with the live Internet site - an unsuccessful script update, an unintended deletion of some file or of your whole database, etc. Restoring the Internet site the way it was will take away or reduce the damage the problem may have caused, which is by all means a better alternative than having to rebuild your entire website from scratch. Although you can download a copy of your content on your laptop or computer, keeping a backup is a feature that the majority of web hosting providers offer as part of their plans. You'll have to check out how frequently they do that, though, because some providers generate a backup only once every 7 days, which can be far from enough for a booking website or an e-commerce portal where the data is updated each day. Make sure that you see how easily a backup could be restored, which can be critical if some issue appears on your website.