Putting on my consumer hat, I really don't know why I need this over Android TV. Is it an upgrade? Does it have new features? Unclear. My Android TV already had Google Assistant on the remote and could "Hey Google, Play Tiger King."
"Android TV" isn't really a thing for consumers. You buy a media box or TV which is powered by it. If you like that device, great. If not, buy a Chromecast.
Android TV is definitely a thing for TV customers. My TV was sold to me as an "Android TV with Chrome cast built in". Now I'm worried this is going to turn into the usual Google abandon ware.