Every smart TV is like that now. Every single one has ads of some kind, at least that I've tried. I mean there might be one weird knockoff brand that doesn't but chances are it's got even larger problems, and forget about finding apps for it.
But yeah, I have my TV connected to the internet. One of the things I had plugged in to my old "dumb" TV was a Chromecast, and the Android TV has one built in... but that requires it be on the internet for it to work. It is running Android so you bet your ass I loaded it up with all sorts of sideloaded goodness (Revanced, SmartTube, Retroarch to name a few). I just haven't gotten around to replacing the launcher to get rid of the ads, since it's a bit involved.
Oh, also it didn't originally have ads, that came in an update about a year later. I'd care more if I spent much time on the home screen, but most of the time the TV's just displaying the output of the Roku.