Why does everyone like vertical tabs? Today my tab icons are so small because I have so many. Monitors are wider than they are taller. What am I missing?
What you're missing is that "vertical tabs" in this context isn't talking about tabs literally turned on their side. We're talking about tabs that are still horizontal, but instead of arranging the tabs along the top of the screen, and shrinking their width when there's no room left, they're given a fixed width and arranged in a vertical list on one side of the screen. The best implementations of this (such as Sidebery, which the previous screenshot is from) also allow tabs to be nested in a collapsible tree structure.
You sound like you'd really like the tree-style tabs offered by Sidebery on Firefox, or that's built into Edge. Give it a try!
It has better customization, better performance, and tab groups. I used TST for many years, switched to Sidebery only a few months ago. You can do stuff like set it to where tabs only activate on releasing the mouse, so you can rearrange unloaded tabs without activating them, or make it so middle clicking the tab close button unloads it instead. You can also rename tabs!
Exactly. The monitors are wide, but websites usually are not. They are made with smartphones in mind which are of course vertical.
So you either have dead space on websites or on sites that do scale (like this one right here), I'd actually prefer it to be more compact, since I find it more comfortable to read comments that are less wide.
In all the most read languages, text is read most easily horizontally. That means that if you want to be able to read the tab titles, they need to be very wide. If they are stacked on top of each other, they can have a fixed width that you're willing to sacrifice, and then you can read the titles easily and scroll through them quickly. They pack very tight (one line) vertically. They don't compress as much horizontally while keeping the titles legible. Using only icons and packing them tight is hard to parse, because horizontal lists are harder to parse than vertical lists.
Further, because monitors are so wide, even one line (and especially one line with all the padding that is required for a UI element to be comfortable to parse) spanning the entire width of the monitor is a felt sacrifice. The width of a normal website title sacrificed horizontally for the entire height of the window on the other hand isn't felt as strongly.
Firefox has "minimum tab width" which takes care of exactly that and works perfectly. Unlike an "experimental" feature in some surveillance Browser by Google
They are awesome. To me at least, but only if you save space by hiding the regular tab bar and it is easier to manage tabs since they are now closer together. Also, if you make the right --or left, it is up to you, I pick right-- sidebar auto hide and letting just the icons show. You do gain a lot of extra space. Mind you, you need to enable CSS via About:Config. On too of, before, using say, Sideberry. I like you thought I did not like it but now that I have tried it. I simply will not go back. I have a userChrome.css file that place on all my machines on a fresh install, now.