My mother who hates every piece of technology and gets frustrated to the point of tears when things don't work like they did yesterday was just fine with a Chromecast. There's no separate Chromecast to learn, manage, or deal with. It's, effectively, a way to mirror your phone to your TV.
I regularly recommended them to people even with Smart TVs and stuff. There were often bugs, UI issues, general confusion... "Just plug this thing in and then use your phone as a remote" added a lot of value.
I don't know why I'd ever want a "Google TV". For $100 what does this give me over the crappy Smart TV UI I've already got? Do I really want to deal with Google's privacy track record over Apple's to save $40?
If you want a modern TV with correct colours, HDR, and useful inputs, you have to stop yourself from connecting a smart TV to the internet. There's just no other way. Roku's OS is absolutely usable without ever configuring it for internet access, and my particular brand of choice, TCL, offers an option to update the OS with a USB stick.
I use my TV with an AV receiver, and HDMI-CEC switching means the TV remote is literally hidden away. The TV has no say in what's happening to it at all.
Weird thing about this is the best thing about Chromecast is it’s not an Apple TV form factor and experience and the worst thing about Apple TV is it’s not a Chromecast style stick.
I just don’t see where a TV would even exist that doesn’t offer what’s in the box built in already, but I definitely know a lot of TVs where Chromecast or AirPlay just doesn’t work on the base unit.