If we want to be cynical we can say they did the same they always do, made a film because they wanted to make money. Sure it was kind of an untapped resource but I don't think they were wanting to beat Marvel by doing a female superhero film first and it certainly wasn't to tick a box. They wanted to do it because she's a character well known around the world. Infact she's an icon and they finally had a pitch they finally believed in. They didn't make it to simply make a female orientated superhero film first.
I don't believe they did either, but I do believe they knew this was the one area they had over Marvel, so the incentive was there to finally make an real effort to bring the character to screen. If this film worked they suddenly put themselves in pole position for female superhero films, and with the roster of female characters at their disposal a critical and box office win would be further incentive to tap into that roster.