YouTube has been for many years now predominantly seen through a mobile device. As shown in the graphic this is no longer the case. In 2022 the forecast is to see YouTube consumption on mobile falling (for the first time) below 50%.
It remains seen on mobile devices in a significant percentage, at least for the coming years, but people are now enjoying it more and more from their couch (or chairs).
The growth is significant (and it is eroding the mobile consumption) on smart television. I wonder if one of the reason is the higher definition supported by YouTube, up to 4k, that becomes a plus if watched on a hi res television (a smartphone screen is too small to appreciate hi res).
Notice that in absolute terms mobile access to YouTube continues and will continue to grow in the coming years, but less than its use on smart televisions. Also interesting is the fact that the total time spent in watching television is not expected to grow, hence a greater share of our eyeballs will be captured by YouTube in the coming years.
Google can smile!