As a former graphic designer. I believe the intention of tapering the emitter at the end is to allow enough clearance for the heads of the fasteners that are holding the bunny ears in place.
If the emitter sat flush with the shroud, you'd have no room to install the screw. So in essence you cannot have the bunny ears without having the tapered emitter.
However, to have the emitter flush with the shroud, it possibly could have been designed to use a countersunk head style of screw. Which would involve careful drilling with a properly tapered bore to allow the screw to seat itself through the shroud and into the base of the bunny ear, then the head of the fastener would sit fairly flush with the underside allowing for a more straight and not tapered emitter.