Windows tend to work slightly better after running into the ground than cameras, electrical systems and screens do.

(A broken window still lets you see outside)

You don't need to have a window on every seat. You could have a few real windows on the side and complement the missing ones by screens.

Doesn't seem like the kind of thing you can rely on in an emergency.

Maybe, though such footage would be useful in a black-box for post-incident/post-flight analysis as a visual comparison to the recorded control/instruments - could only help.