It works but it completely breaks standard behavior.
Arrow keys can work normally, or select paragraph, or do nothing, or behave erratically.
Page-up/down make work or may not work, and may have some weird interaction with the arrow keys.
The scrollbar is nonstandard on Chrome. It is not completely broken but the mouse pointer is wrong.
Mouse-based scrolling works, it is the only thing that seems to work as expected.
Reader mode doesn't work.
I don't understand why websites go out of their way to reimplement perfectly good browser behavior. I am sure it is a lot of hard work, and it is almost always done poorly, in fact, I am not sure there is a way of doing it correctly.