Yep. While Sidebery, TST, etc have done about as well as they can given the limitations of extensions, the resulting vertical tab experience is half-baked without userChrome mods. It's also still kinda janky even with the mods unless one spends time polishing out all the edge cases, but then there's a high chance the mods will randomly break in weird ways after an update one day. There's real value in having the feature be native.