It's more than just privacy. It allows you to visit .onion sites, which will not load in a traditional browser. As a harmless example, this is Duck Duck Go: https://duckduckgogg42xjoc72x3sjasowoarfbgcmvfimaftt6twagswzczad.onion/. Trying to click that in a normal browser doesn't work because they don't support the onion network. But using the Tor browser unlocks that as well as all sorts of nefarious sites that you can't access through a "normal browser"