> There's no benefit gained, whatsoever, from moving content to the title bar

The one benefit I can see is to gain some extra vertical space on the skinny 16:9 screens, especially now that the task bar in windows 11 got thicker and can no longer be moved to a side. They, of course, still haven't gotten around to fixing the auto-hide behavior, so that's still not an option.

The rare times I have to use windows, I use edge and I quite like the vertical tabs. This allows for a usable title bar, too.