Vlad just came here to add that this feature ("auto show/hide vertical tabs on mouse/pointer hover" -- exactly like the MacOS dock) is still very much desired by at least one devoted user/fan...
Vertical tab-centric UI -- for whatever reason -- is increasingly being perceived as a key identifying characteristic of the so-called "modern"/"paradigm-shifting"/"standards-reimagining"/etc it-browser (i.e. Arc, Beam, SigmaOS, Stackbrowser... strangely enough, some aspects of Edge).
Slick vertical tabs signal to browser refugees that their latest download has the potential to be their new, 2023-approved daily driver. But many browser refugees -- especially those confined to 13-15 inch screens like myself -- simply can't tolerate the loss in content real estate of static vert tabs, or the hassle of clicking a button/pressing a key to get that real estate back (or, conversely, to get our slick vert tabs back).
Vert tabs that auto-show/hide on mouse/pointer hover ensure that a user is able to experience what the great philospher Miley Cyrus once called "the best of both worlds".
I love Orion because it tastefully blends the new/progressive with the time-tested/carefully considered (ex: "extensions? go crazy! Chrome AND FF -- knock yourself out, kid!" + "Safari devs were right that excessive customization/theming is deleterious to the ultimate goal of content taking precedence over the vehicle for experiencing it"). And I think this feature would align perfectly with that most noble vision.