its so when you accidentally click a link you still have the chance to close the page without actually having opened that page.
And when you are not suffering from crippling osteoporosis, you have to wait for a few seconds. Maybe make it optional?
It is also looks more like shill tool some platforms use to collect leaving statistic in most obtrusive way possible (i.e. also putting nasty confirmation dialog if you really want to visit nasty hacker site with green frogs and ask parental permission)