If you manage a site, having a backup is something rather important, specifically if you have important info or you have invested time and money in building the site. There are numerous scenarios why you may need a backup - if you update a script and something breaks down, if you delete a file or an entire folder unintentionally, and so forth. Having regular backups will help you avoid any loss of information or at least minimize the damage, which is still better than losing the entire site. You'll be able to download a copy of your content on your computer occasionally, but as you simply can't do that after every single change, you have to rely on the backups that your hosting provider generates. Since that is something very crucial, you need to ensure that they keep up-to-date backups, considering that a backup performed once every one or two weeks will not do any good in case you run a site such as an online store or a holiday accommodation booking portal.