You mean like isolating cookies?
Like integration state partitioning for the entire browser context, user-controllable?
Like adding vertical tabs?
Like background wallpaper options for new tab independent of themes?
Like site translations?
Like working on tab groups?
Like working on tablet UI options?
Like .. okay I'll stop.
Like with red traffic lights vs green traffic lights, always keep in mind that your brain does not want to actively notice/recall things going well. It's when things are annoying/interrupting that you remember.