Pretty book chapters

, but not Gaudy

And use some chapter head margins, but not be overly wasteful of the screen height.
And who need side margins for basic content?
On a paper book the edge of the paper was the
edge. You did not want text right on the edge of the paper (worse if the registration slipped and text got cropped).
On a screen, there is a Bezel to provide a visual frame and the margins need only be a few px to allow for display overscan/mechanical misalignment.
IMHO there is no reason an e-book can't be as
nice as the paper cousin.
Nice, not necessarily an exact copy