There is something to be said about a girl that (a) gets along with other girls in a group setting ("cute shoes!") and/or (b) has a solid group of girlfriends. Conversely, there is shit to be talked about the girl that (a) glares at every other female within a 15ft radius and/or (b) claims to just "not get along with girls." Yeah yeah girls can be catty/dramatic/etc but if you don't have close girlfriends that probably means there is something wrong with you.
Being able to "hang with the guys" has its appeal, but guys appreciate a certain degree of femininity and sometimes it's nice having your own separate interests you can enjoy separately with people who share the same gender (ie- fantasy football vs 90s themed sleepover parties with wine, girltalk, and a screening of Sarah Jessica Parker's Girls Just Wanna Have Fun).