I had a lawyer friend who said that photos were expected on resumes and websites, something she hated despite the fact that she felt she benefited from it. Part of it is that firms and clients want to see a professional image, but yeah, it also brings in all the usual gender/age/ethnic biases.
To answer "why wouldn't they play that card" - plenty of women know their looks/gender might get them in the door when it wouldn't otherwise, and feel like imposters even if they are highly qualified and a great match for the position.
They may want to work at the kind of company that hires them because of their accomplishments, not one that says "oh, we need more women." One reason: a company that hired them because they were a woman may have done so just to fill a quota and there's no genuine interest in them succeeding and advancing...whereas another employer might see their talent and work to help them succeed. Or a company that hires just to fill quotas might put women in positions they aren't actually qualified for. Etc.
