Well... to most people it's still a computer and not a TV. That's why they buy both :). But they purchase computers like TVs (a single product with practically no user serviceable parts).
True people buy both, although most people who buy a device that you and I are calling a 'computer' those people are buying it strictly as information consumers, and to a lesser extent codified information producers (like instagram or uploading a youtube video). They will never change its configuration, or attempt to program it in any way. It is an information appliance, like a TV, except with a keyboard and a web cam.