You learn to rely on a few basic movements and use your voice to the greatest extent possible to convey your emotions. So there was a technical challenge there and a responsibility to create a character from behind the mask.
It occurred to Susan that men were always waiting for something cataclysmic-love or war or a giant asteroid. Every man wanted to be a hot-headed Bruce Willis character, fighting against the evil foreign enemy while despising the domestic bureaucracy. Men just wanted to focus on one big thing, leaving the thousands of smaller messes for the women around them to clean up.