Yep. You’d think that websites would be easier to view in landscape orientation (with Desktop Mode enabled of course, since otherwise the mobile UI is designed for portrait mode). But it never seems to work that way. Clunky widgets/UI choices are a big part of this, plus the fact that if I’m on a website I probably want to type something, and trying to use the keyboard in landscape mode leaves me with naught but a sliver of the actual webpage still visible.
Using portrait mode splits your screen into half keyboard, half actual screen, giving a good balance between navigation and typing.