The internet connection to a smart TV doesn't go anywhere near a computer. It travels through your phone cable to your router, from where it's sent to your TV. You don't need a computer at all to use a smart TV.
However, unlike your computer (which might have, say, your banking details stored on it), there's very little on a smart TV set that could be of interest to hackers, simply because it's not used to store much data. I suppose that it's theoretically possible that someone could hack a smart TV to steal, say, the users' Netflix credentials, and then sell them onto others but there are far, far easier ways for hackers to make their money. I'm certainly not worried about the extremely remote possibility of my TV being hacked!