I'm replying here from the POV of a person who watches gaming channels all day (since I'm a gamer.)
I'm used to seeing things in full screen, captured video from screen; however, what I saw here was a person taking their camera into their day with them. Switching to a full-screen of the video game would have been oddly "dishonest" to the audience because that's not how someone actually sees a video game who is out in their day. They see it on a screen (TV in that case) and with the camera watching it became our POV for someone who came in, sat down, and played.
It was a much more organic way to convey the experience from someone who's not posting gameplay, but instead posting a "this is me gaming."
I think the experiment went well.