The bonus of using a TV is that you're not destined to have to sit in one place, you can use a wireless keyboard and mouse, so if you have a living room dining room set up together, you can put on your netflix or youtube, take the wireless keyboard and mouse to the dining table or coffee table and do other things, or watch them from the sofa. That's a big advantage over using a small monitor on a computer desk.
You can also change the resolution and screen size on the computer so that it isn't full screen on the TV, if you are using it up close.