Personally. I hate this move to Mobile design. I told everyone last year when they started pushing the new YT Creator that it was a move to Mobile platform design and it had nothing to do with making it better. This video literally confirms what I said. I don't mind YT being formatted for mobile on the Viewers side, but when it comes to DESIGNING and Creating, it needs to be for Desktop on the creator's side. No professional videographer on earth uses a smartphone to create movies. Show me a Hollywood movie that was created on a smartphone. Movie creation is done on a DESKTOP. Professional work is done on a Desktop, not a smartphone. We watch things on a smartphone.
There will never be a better interface to detailed professional work than a Keyboard and a Mouse.
This is what happens when you let gadget geeks decided what is best.