I had TVs back in the early 00’s with this feature and I loved it. I had to buy a multiviewer online to do it with my main TV in my house but it’s a very inelegant solution. I can split HDMI sources that way, but I’d love to be able to split roku apps and HDMI sources on my roku TVs and even just apps on my 2 TVs with standalone Roku devices. (If you’d make a new roku that was also a multi viewer and could split both I would buy that).