DF feedback: more flicking between and less side by sides
I'm sure their analytics also show that most people are watching videos on mobile devices. These tend to have small screens. Personally I do too in a pinch when commuting etc but if it's something I care about I'll wait until I'm on my PC at home. Having a 3, 4 or 5+ way side by side split makes it just plain difficult to spot differences as the main or only way of showing them. And I feel DF in recent years tends to sometimes only or mainly present it this way.
I much prefer the "optician method" of flicking between stills or video in full screen. Then you can cap off at the end with side by sides.
This thought came to light when watching Hardware Unboxed's graphical optimisation video for Forza Horizon 6. Again beating DF to the punch.