And why I say so? Because there was no Bookmarks panel for so many years, that I've used to use Chrome Extensions (Neater Bookmarks or, currently, Minimal Bookmarks Tree) which I consider a lot better (size and shortcuts settings) and to treat side panel buton as a shortcut to the "big" b\Bookmarks Manager. Actually that become a really convenient and to be honest i don't want to lose that because after five or six years since Opera Blink release their authors finally decided that bookmarks on the side are good idea.
And yes, I don't like the history panel too.
BTW why all these graphic elements are so huge, so heavy? Even though almost everything is plain white it's also so big, with so much free spaces, so much weight... Huge overwhelming tabs/title bar, huge heavy floating panels, huge quick settings panel with huge colour switches and a lot of empty spaces... It's 2019 and I see that UI is still designed for the only one right resolution and one specific DPI. What about people who are using different combinations than FHD + 100 DPI or 4k + 150/200 DPI? UI in these cases really doesn't look good. It becomes wore and worse with every single update.