Actually, both smart TV and an Android TV box are one and the same. They both have similar features which allow you to stream content directly from the net. The only difference between the two is that smart TV already has the features of streaming (in-built). Whereas the Android TV box is an external device which let you turn a normal TV into a smart TV. Therefore if you already own a smart Tv you don't need a TV box. But if you don't, then the TV box would be a cheap and convenient way to upgrade your TV.