Most people do that to use integrated streaming apps. This is less expensive than buying an Apple TV/Chromecast
My dad runs Apple TV since his screen is older, and it's marginally better than my Vizio because most of the time YoutubeTV continues where it left off when turning TV back on which is nice.
It just makes things so much more frustrating when you're providing support for the less technically inclined.
In fact that's the reason these ads are there - a lot of people can't be convinced to use an external device to escape them. If everyone used Apple TVs/etc, there would be no built-in ads because it's just not worth the trouble.
https://www.amazon.com/Android-Streaming-Control-Assistant-1...
And Chromecast is arounf $50. That's really not a high price for being able to control your own TV.
But the experience of using the integrated apps is just better. It all just works out of the box, there are basically no ads (some "recommended content", but it's pretty unobtrusive) and I don't need to use my phone or worry about why youtube or netflix have randomly decided not to see the chromecast.