Have you considered the possibility that "working twice as hard" not just refers to the actual work but also the fact that women most likely have a lot less degrees of freedom when it comes to presentation, skill and persistance than men? Meaning that there's very little room for them to mess up, not look perfectly presentable at all times, not have a "bad night", not being to drunk, too loud without being judged or dismissed. As well as enduring countless times being viewed as a piece of meat before reaching a level of success where they are acknowledged for their accomplishments. If a dude is a shitty singer it's on him. If a woman fucks up, it's implied that it reflects poorly on all woman. So yeah, I'd say women, still, has more of an uphill battle then men to succeed in metal. Just because men are the norm and women are considered "the other", a quaint novety.
As such, I see no problem with special awards for women. All awards are meh anyway. And if it brings more rolemodels to young girls and women, why not? Where's the harm?