You don't actually use the bar that often, so having it at the bottom doesn't improve much. In fact, it will mostly be in the way. Bookmarks on the other hand

You don't actually use the bar that often, so having it at the bottom doesn't improve much. In fact, it will mostly be in the way. Bookmarks on the other hand are used often and the new updates requires 3 clicks to get to them (previously 1). So this is a classic case of UX designer not knowing how people use his software and just doing changes he thinks are cool.