I think John Byrne is clearly trying to evoke a black-sporting Batman in almost everything he's done.
Arguably in almost every comic that Batman wears a primarily blue cape and cowl the face of the cowl is always black. So are we to believe that the cowl is literally blue except for this round area directly on the face of the cowl, which is black with blue eyebrows? Or is it conveniently shadowed all the time, even in broad daylight? Or is it supposed to be evocative of black?