Pure marketing stunt. Most Blurays are probably higher quality even if they are "only" 1080p. But they have bitrates hovering somewhere between 10 to 20 Mbps, while YouTube apparently uses <1Mbps even for 4k.
Incidentally it could be interesting to see some kind of visual quality vs bitrate vs resoltion -chart, ie what would be the optimal resolution for some bitrate.
Incidentally it could be interesting to see some kind of visual quality vs bitrate vs resoltion -chart, ie what would be the optimal resolution for some bitrate.