And I can't for the life of me even understand what the purpose is! The URL bar already had a very noticeable focus state outline. Are there users who couldn't tell it was in focus?

People on reddit have been complaining about how the bookmarks bar is harder to access now. The developer response has been something to the effect of "it's only covering the bar by a few pixels, it's really not a substantial difference."

I'd be inclined to agree with the evelopers, except, what is the advantage of that trade-off? Sure, you're only making the bookmarks bar very marginally harder to use, but, it's still something, and if users aren't getting anything out of it in return... why do it?