Originally Posted by Gagarin Gambit
Issues arise only with unusual formatting
This is precisely the issue here.
In a screenplay, the line spacing, indentation and character emphasis on the page give queues to structure.
Joydot can correct me if I'm wrong, but it's important to be able to see, at a glance, the page formatting as the writer typed it.
(also, with a rule of thumb of one page per minute screen time, even the page numbers are a structural cue.)