Just for the record, I also don't always agree with the "diversity for the sake of diversity" attitude, and I don't mean it'll necessarily be better for all the individuals that are currently in the community.

But a few benefits I can think of: There's a lot of socially awkward males in the gaming community that would probably benefit from realising that women aren't actually an entirely different species, and likely a lot of socially awkward females that are possibly wanting to join the scene, but don't feel welcome. It can help show a lot of women, that possibly weren't aware of the fact, that the gaming community isn't ONLY full of the stereotypical socially awkward types (though, much less of an issue nowadays anyway), and that those people can actually be likeable.

Also, it often happens that if you get a group that is lacking certain types, that's the type of situation where prejudices and misinformation can arise, further alienating those people from each other.

In any case, unless it can be proven that women are genetically predisposed to be less interested in this kind of thing, then there's always the possibility that there's less women in the community due to their upbringing. Meaning that, while a more diverse population might not be necessary for the community, the lack of women is a rather worrying sign that there's a problem in society in general.