Why is this preferable to authentication using cookies?
Both BasicAuth and Cookie reception are features included in nearly every browser offering - it's generally how you actually check resource authorization that's the hard part of Auth - the actual technical "Get a cookie from a browser" and "Check the BasicAuth headers" portions are pretty simple - in fact getting a cookie is arguably easier in most cases. Especially since a popular serverside programming language (PHP) has streamlined session handling to the point that most programmers going from it to other serverside languages get confused when there isn't a $_SESSION equivalent that you just inspect with the tap of a button.
You can look at functionality like Apache’s mod_authnz_ldap as an example of built in account management that integrates with HTTP basic auth.
The only difference I can see is that the browser has a native control for one of them, though that control cannot be customised by the site.