You do have to remember he is a business man and although we know , and I'm sure he knows, that there are very talented women fighters out there, the marketability outside of Carano and Rousey really isn't there. Even Cyborg has some hype about her because she was basically a beserker that punched the face off everyone she fought. Dana was going to put Carano in the octagon but then she was punched into retirement by Cris Cyborg. Now that there is another hype train rolling through, it make sense for him to make the move now. Why let Rousey's popularity go somewhere else? Now is the time to take the chance.
He's also said that if Caramouche wins the fight, it's not like he's canning the division. They aren't going to end the investment that fast. Plus the UFC seems to give legitimacy to things. No one gave a shit outside of the diehards about the flyweights but now people are excited to see the "Little Guys" fight and it will be the same with women.
I'm hoping this brings in alot of the Hook N Shoot girls. I'd also love to see Tara LaRosa, Marloes Connen, Meisha Tate, Zoila Gurgel and most importantly Megumi Fujii in the octogon.