On February 1, 2017 at 00:05, grassynoel said...
One reason might be the built-in streaming apps (amazon, netflix, and youtube are some) are a source for 4K video. Roku and some others do offer 4K players, but its easier for me to program a remote (and sell a system) with the tv as the streaming source.
My understanding is that some TVs (like Sony) deliver better 4K through the TV app versus streaming boxes.