Many do use XenForo as their entire website and not just their forum. Often sites can set a news page or similar as their actual homepage, which will just be a page provided by an add-on.
There are a few ways to do news. If you want to showcase posts only you've written, you'd put them in a forum. You could also set up an RSS poster to post threads from an external news source into a forum. Then you can use an add-on like XenPorta to display these threads nicely, and set that as your home route. For basic needs, there's actually also the add-on in the XenForo dev tutorial which (iirc) displays threads from a forum on a separate page.
I don't think there is an add-on for reviews, though.
In general, you can definitely use XenForo as a website. For specific features, you'll need an add-on providing that functionality of course.