Smart TVs are great, in that you can watch Netflix directly on your TV, other streaming services (if supported), browse the web, play (crummy) games, all in addition to cable / satellite / OTA.
But Smart TVs are not great, in that they report back to their manufacturer everything you do. /mobile.nytimes.com/2018/07/05/business/media/tv-viewer-tracking.html
Also they can essentially shut you down if your firmware is out of date, you haven't agreed to some legal terms, or if the TV just becomes obsolete. Then you have a big expensive box of e-waste.