> They could be garbage in every other way, but at least they have that
Not really, they could also not implement keyboard input for some interactions and only react to mouse. You could have a click-to-open-url in your terminal without a keyboard fallback setup. Of course, you could set it up, but that would be "polish if you put in the effort" There is no limit to garbage.
> Also once your workflow is increasingly keyboard based (like when using a tiled window manager),
Exactly, for example, you've set your Windows key to be reponsible for all window-based movements, so you have it move/resize app windows and want to have the same key help you move/resize "inner windows/panes/columns" in a TUI app. Well, tough luck, the terminal doesn't even recognize this modifier!
Again, "as polish if you put in the effort" you can achieve anything via some external remapping to supported keys, but "otherwise" you don't have keybindings, and don't even have generalized fallback common (though not universal, again, there is no limit to garbage) to GUIs.
Or you'd be unable to bind some key combo because in a terminal that key combo is equivalent to regular typing and you need to timeout to differentiate between the two, so a permanent friction.
> tab is swallowed by an input so you can't even tab past a component
Of course you can, use your keyboard to move the mouse pointer and click outside of the input field. All pure organic keyboard-based interaction! "They could be garbage", but at lest you have that keyboard-based option (yes, only "polish/put in effort")