I use to think the main answer was lack of ads, because all smart TV’s built in UIs just plasters ads all over the place and it is just super annoying. But then I once actually used a TV’s built in interface, as well as a Roku device, and couldn’t believe the lag. You click on an app, wait 20 seconds, it finishes opening, click on a tab, wait another 20 seconds, etc etc. it absolutely blew my mind, and I couldn’t believe that people actually put up with that when an Apple TV is so cheap. And then on top of that you have the App Store with pretty much every app you can think of, all the AirPlay functionality, use your iPhone as a remote, smart home hub, the list goes on and on, all while being super fast and snappy and with zero ads. Seriously every single person who owns a TV should have an Apple TV and it’s crazy that they don’t, the only people who don’t are the ones who haven’t experienced it and are unaware how much better it is.