Nope, the Nightwing mask is "un-Superman-like" too. That's why he wore it...as a disguise!
As for Superwoman, the mask was necessary in the first story, else Kristin would have said "Hey, that's me!" on page one and she'd get no surprise later.
But I agree it should have been dumped by the second appearance. As super-hero disguises go, not being born yet is a pretty hard one to beat!